That single line of output comes from the first line of the getXconsole method in /usr/share/acpi-support/power-funcs

falken@wopr:~$ fgconsole
Couldn't get a file descriptor referring to the console
falken@wopr:~$ 

The strace shows some permission denied errors for opening devices in /dev/ but I dunno if that's normal or not. I think that that means getXuser (which is overridden in the main powerbutn.sh) is never called, and so XUSER is never set. This means the script falls down to the bottom. 
Bah.

falken@wopr:~$ strace fgconsole
execve("/bin/fgconsole", ["fgconsole"], [/* 42 vars */]) = 0
brk(0)                                  = 0x8693000
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
mmap2(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb77bd000
access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or directory)
open("/etc/ld.so.cache", O_RDONLY)      = 3
fstat64(3, {st_mode=S_IFREG|0644, st_size=126614, ...}) = 0
mmap2(NULL, 126614, PROT_READ, MAP_PRIVATE, 3, 0) = 0xb779e000
close(3)                                = 0
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
open("/lib/tls/i686/cmov/libc.so.6", O_RDONLY) = 3
read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0000m\1\0004\0\0\0"..., 512) = 512
fstat64(3, {st_mode=S_IFREG|0755, st_size=1405508, ...}) = 0
mmap2(NULL, 1415592, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x2b5000
mprotect(0x408000, 4096, PROT_NONE)     = 0
mmap2(0x409000, 12288, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x153) = 0x409000
mmap2(0x40c000, 10664, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x40c000
close(3)                                = 0
mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb779d000
set_thread_area({entry_number:-1 -> 6, base_addr:0xb779d8d0, limit:1048575, seg_32bit:1, contents:0, read_exec_only:0, limit_in_pages:1, seg_not_present:0, useable:1}) = 0
mprotect(0x409000, 8192, PROT_READ)     = 0
mprotect(0x804a000, 4096, PROT_READ)    = 0
mprotect(0xe1a000, 4096, PROT_READ)     = 0
munmap(0xb779e000, 126614)              = 0
brk(0)                                  = 0x8693000
brk(0x86b4000)                          = 0x86b4000
open("/usr/lib/locale/locale-archive", O_RDONLY|O_LARGEFILE) = -1 ENOENT (No such file or directory)
open("/usr/share/locale/locale.alias", O_RDONLY) = 3
fstat64(3, {st_mode=S_IFREG|0644, st_size=2570, ...}) = 0
mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb77bc000
read(3, "# Locale name alias data base.\n#"..., 4096) = 2570
read(3, "", 4096)                       = 0
close(3)                                = 0
munmap(0xb77bc000, 4096)                = 0
open("/usr/lib/locale/en_US.UTF-8/LC_IDENTIFICATION", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/lib/locale/en_US.utf8/LC_IDENTIFICATION", O_RDONLY) = 3
fstat64(3, {st_mode=S_IFREG|0644, st_size=373, ...}) = 0
mmap2(NULL, 373, PROT_READ, MAP_PRIVATE, 3, 0) = 0xb77bc000
close(3)                                = 0
open("/usr/lib/gconv/gconv-modules.cache", O_RDONLY) = 3
fstat64(3, {st_mode=S_IFREG|0644, st_size=26048, ...}) = 0
mmap2(NULL, 26048, PROT_READ, MAP_SHARED, 3, 0) = 0xb77b5000
close(3)                                = 0
open("/usr/lib/locale/en_US.UTF-8/LC_MEASUREMENT", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/lib/locale/en_US.utf8/LC_MEASUREMENT", O_RDONLY) = 3
fstat64(3, {st_mode=S_IFREG|0644, st_size=23, ...}) = 0
mmap2(NULL, 23, PROT_READ, MAP_PRIVATE, 3, 0) = 0xb77b4000
close(3)                                = 0
open("/usr/lib/locale/en_US.UTF-8/LC_TELEPHONE", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/lib/locale/en_US.utf8/LC_TELEPHONE", O_RDONLY) = 3
fstat64(3, {st_mode=S_IFREG|0644, st_size=59, ...}) = 0
mmap2(NULL, 59, PROT_READ, MAP_PRIVATE, 3, 0) = 0xb77b3000
close(3)                                = 0
open("/usr/lib/locale/en_US.UTF-8/LC_ADDRESS", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/lib/locale/en_US.utf8/LC_ADDRESS", O_RDONLY) = 3
fstat64(3, {st_mode=S_IFREG|0644, st_size=155, ...}) = 0
mmap2(NULL, 155, PROT_READ, MAP_PRIVATE, 3, 0) = 0xb77b2000
close(3)                                = 0
open("/usr/lib/locale/en_US.UTF-8/LC_NAME", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/lib/locale/en_US.utf8/LC_NAME", O_RDONLY) = 3
fstat64(3, {st_mode=S_IFREG|0644, st_size=77, ...}) = 0
mmap2(NULL, 77, PROT_READ, MAP_PRIVATE, 3, 0) = 0xb77b1000
close(3)                                = 0
open("/usr/lib/locale/en_US.UTF-8/LC_PAPER", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/lib/locale/en_US.utf8/LC_PAPER", O_RDONLY) = 3
fstat64(3, {st_mode=S_IFREG|0644, st_size=34, ...}) = 0
mmap2(NULL, 34, PROT_READ, MAP_PRIVATE, 3, 0) = 0xb77b0000
close(3)                                = 0
open("/usr/lib/locale/en_US.UTF-8/LC_MESSAGES", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/lib/locale/en_US.utf8/LC_MESSAGES", O_RDONLY) = 3
fstat64(3, {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
close(3)                                = 0
open("/usr/lib/locale/en_US.utf8/LC_MESSAGES/SYS_LC_MESSAGES", O_RDONLY) = 3
fstat64(3, {st_mode=S_IFREG|0644, st_size=57, ...}) = 0
mmap2(NULL, 57, PROT_READ, MAP_PRIVATE, 3, 0) = 0xb77af000
close(3)                                = 0
open("/usr/lib/locale/en_US.UTF-8/LC_MONETARY", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/lib/locale/en_US.utf8/LC_MONETARY", O_RDONLY) = 3
fstat64(3, {st_mode=S_IFREG|0644, st_size=286, ...}) = 0
mmap2(NULL, 286, PROT_READ, MAP_PRIVATE, 3, 0) = 0xb77ae000
close(3)                                = 0
open("/usr/lib/locale/en_US.UTF-8/LC_COLLATE", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/lib/locale/en_US.utf8/LC_COLLATE", O_RDONLY) = 3
fstat64(3, {st_mode=S_IFREG|0644, st_size=1170770, ...}) = 0
mmap2(NULL, 1170770, PROT_READ, MAP_PRIVATE, 3, 0) = 0xb767f000
close(3)                                = 0
open("/usr/lib/locale/en_US.UTF-8/LC_TIME", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/lib/locale/en_US.utf8/LC_TIME", O_RDONLY) = 3
fstat64(3, {st_mode=S_IFREG|0644, st_size=2454, ...}) = 0
mmap2(NULL, 2454, PROT_READ, MAP_PRIVATE, 3, 0) = 0xb77ad000
close(3)                                = 0
open("/usr/lib/locale/en_US.UTF-8/LC_NUMERIC", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/lib/locale/en_US.utf8/LC_NUMERIC", O_RDONLY) = 3
fstat64(3, {st_mode=S_IFREG|0644, st_size=54, ...}) = 0
mmap2(NULL, 54, PROT_READ, MAP_PRIVATE, 3, 0) = 0xb77ac000
close(3)                                = 0
open("/usr/lib/locale/en_US.UTF-8/LC_CTYPE", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/lib/locale/en_US.utf8/LC_CTYPE", O_RDONLY) = 3
fstat64(3, {st_mode=S_IFREG|0644, st_size=256324, ...}) = 0
mmap2(NULL, 256324, PROT_READ, MAP_PRIVATE, 3, 0) = 0xb7640000
close(3)                                = 0
open("/proc/self/fd/0", O_RDWR)         = 3
ioctl(3, SNDCTL_TMR_TIMEBASE or TCGETS, {B38400 opost isig icanon echo ...}) = 0
ioctl(3, KDGKBTYPE, 0xbfdeec3f)         = -1 EINVAL (Invalid argument)
close(3)                                = 0
open("/dev/tty", O_RDWR)                = 3
ioctl(3, SNDCTL_TMR_TIMEBASE or TCGETS, {B38400 opost isig icanon echo ...}) = 0
ioctl(3, KDGKBTYPE, 0xbfdeec3f)         = -1 EINVAL (Invalid argument)
close(3)                                = 0
open("/dev/tty0", O_RDWR)               = -1 EACCES (Permission denied)
open("/dev/tty0", O_WRONLY)             = -1 EACCES (Permission denied)
open("/dev/tty0", O_RDONLY)             = -1 EACCES (Permission denied)
open("/dev/vc/0", O_RDWR)               = -1 ENOENT (No such file or directory)
open("/dev/vc/0", O_WRONLY)             = -1 ENOENT (No such file or directory)
open("/dev/vc/0", O_RDONLY)             = -1 ENOENT (No such file or directory)
open("/dev/console", O_RDWR)            = -1 EACCES (Permission denied)
open("/dev/console", O_WRONLY)          = -1 EACCES (Permission denied)
open("/dev/console", O_RDONLY)          = -1 EACCES (Permission denied)
ioctl(0, SNDCTL_TMR_TIMEBASE or TCGETS, {B38400 opost isig icanon echo ...}) = 0
ioctl(0, KDGKBTYPE, 0xbfdeec5f)         = -1 EINVAL (Invalid argument)
ioctl(1, SNDCTL_TMR_TIMEBASE or TCGETS, {B38400 opost isig icanon echo ...}) = 0
ioctl(1, KDGKBTYPE, 0xbfdeec5f)         = -1 EINVAL (Invalid argument)
ioctl(2, SNDCTL_TMR_TIMEBASE or TCGETS, {B38400 opost isig icanon echo ...}) = 0
ioctl(2, KDGKBTYPE, 0xbfdeec5f)         = -1 EINVAL (Invalid argument)
open("/usr/share/locale/en_US.UTF-8/LC_MESSAGES/kbd.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/share/locale/en_US.utf8/LC_MESSAGES/kbd.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/share/locale/en_US/LC_MESSAGES/kbd.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/share/locale/en.UTF-8/LC_MESSAGES/kbd.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/share/locale/en.utf8/LC_MESSAGES/kbd.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/share/locale/en/LC_MESSAGES/kbd.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/share/locale-langpack/en_US.UTF-8/LC_MESSAGES/kbd.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/share/locale-langpack/en_US.utf8/LC_MESSAGES/kbd.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/share/locale-langpack/en_US/LC_MESSAGES/kbd.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/share/locale-langpack/en.UTF-8/LC_MESSAGES/kbd.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/share/locale-langpack/en.utf8/LC_MESSAGES/kbd.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/share/locale-langpack/en/LC_MESSAGES/kbd.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
write(2, "Couldn't get a file descriptor r"..., 56Couldn't get a file descriptor referring to the console
) = 56
exit_group(1)                           = ?
falken@wopr:~$