It looks like this was caused by MySQL failing to upgrade:
Selecting previously deselected package mysql-server-5.0.
(Reading database ... 345024 files and directories currently installed.)
Unpacking mysql-server-5.0 (from .../mysql-server-5.0_5.0.67-0ubuntu6_i386.deb) ...
/usr/sbin/nscd: relocation error: /usr/sbin/nscd: symbol __nss_services_lookup, version GLIBC_PRIVATE not defined in file libc.so.6 with link time reference
/usr/sbin/nscd: relocation error: /usr/sbin/nscd: symbol __nss_services_lookup, version GLIBC_PRIVATE not defined in file libc.so.6 with link time reference
/usr/sbin/nscd: relocation error: /usr/sbin/nscd: symbol __nss_services_lookup, version GLIBC_PRIVATE not defined in file libc.so.6 with link time reference
/usr/sbin/nscd: relocation error: /usr/sbin/nscd: symbol __nss_services_lookup, version GLIBC_PRIVATE not defined in file libc.so.6 with link time reference
/usr/sbin/nscd: relocation error: /usr/sbin/nscd: symbol __nss_services_lookup, version GLIBC_PRIVATE not defined in file libc.so.6 with link time reference
adduser: The group `mysql' does not exist.
dpkg: error processing /var/cache/apt/archives/mysql-server-5.0_5.0.67-0ubuntu6_i386.deb (--unpack):
subprocess pre-installation script returned error exit status 1
It looks like this was caused by MySQL failing to upgrade:
Selecting previously deselected package mysql-server-5.0. server- 5.0_5.0. 67-0ubuntu6_ i386.deb) ... lookup, version GLIBC_PRIVATE not defined in file libc.so.6 with link time reference lookup, version GLIBC_PRIVATE not defined in file libc.so.6 with link time reference lookup, version GLIBC_PRIVATE not defined in file libc.so.6 with link time reference lookup, version GLIBC_PRIVATE not defined in file libc.so.6 with link time reference lookup, version GLIBC_PRIVATE not defined in file libc.so.6 with link time reference apt/archives/ mysql-server- 5.0_5.0. 67-0ubuntu6_ i386.deb (--unpack):
(Reading database ... 345024 files and directories currently installed.)
Unpacking mysql-server-5.0 (from .../mysql-
/usr/sbin/nscd: relocation error: /usr/sbin/nscd: symbol __nss_services_
/usr/sbin/nscd: relocation error: /usr/sbin/nscd: symbol __nss_services_
/usr/sbin/nscd: relocation error: /usr/sbin/nscd: symbol __nss_services_
/usr/sbin/nscd: relocation error: /usr/sbin/nscd: symbol __nss_services_
/usr/sbin/nscd: relocation error: /usr/sbin/nscd: symbol __nss_services_
adduser: The group `mysql' does not exist.
dpkg: error processing /var/cache/
subprocess pre-installation script returned error exit status 1