resume fails after several suspend/resume cycles

WOL works from suspend mode only.
pm-suspend/resume works flawlessly several times (around 3 to 5 cycles) but then suddenly fails to resume.
In such a case, after magic WOL package was sent, fan starts, harddisk LED is constantly on, CPU gets very hot, but PC is not reacting (no video signal, no network access, no keybord control, ...)

Since I don't know how to get more debug info from the pm-utils, I have no clue what may cause the problem.

Mythbuntu 8.04.1
Board: ASRock Wolfdale 1333-D667 R2.0

>> cat /proc/interrupts
CPU0
  0: 710668 XT-PIC-XT timer
  1: 3720 XT-PIC-XT i8042
  2: 0 XT-PIC-XT cascade
  3: 2 XT-PIC-XT
  4: 6 XT-PIC-XT
  5: 2 XT-PIC-XT
  7: 3 XT-PIC-XT parport0
  8: 3 XT-PIC-XT rtc
  9: 492 XT-PIC-XT acpi
 10: 350099 XT-PIC-XT uhci_hcd:usb1, i915@pci:0000:00:02.0
 11: 876520 XT-PIC-XT uhci_hcd:usb2, ohci1394, ehci_hcd:usb3, yenta, yenta, eth3, Intel 82801DB-ICH4, eth2
 12: 69222 XT-PIC-XT i8042
 14: 55056 XT-PIC-XT libata
 15: 0 XT-PIC-XT libata
NMI: 0 Non-maskable interrupts
LOC: 0 Local timer interrupts
RES: 0 Rescheduling interrupts
CAL: 0 function call interrupts
TLB: 0 TLB shootdowns
TRM: 0 Thermal event interrupts
SPU: 0 Spurious interrupts
ERR: 0
MIS: 0

>> lspci
00:00.0 Host bridge: Intel Corporation 82852/82855 GM/GME/PM/GMV Processor to I/O Controller (rev 02)
00:00.1 System peripheral: Intel Corporation 82852/82855 GM/GME/PM/GMV Processor to I/O Controller (rev 02)
00:00.3 System peripheral: Intel Corporation 82852/82855 GM/GME/PM/GMV Processor to I/O Controller (rev 02)
00:02.0 VGA compatible controller: Intel Corporation 82852/855GM Integrated Graphics Device (rev 02)
00:02.1 Display controller: Intel Corporation 82852/855GM Integrated Graphics Device (rev 02)
00:1d.0 USB Controller: Intel Corporation 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) USB UHCI Controller #1 (rev 03)
00:1d.1 USB Controller: Intel Corporation 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) USB UHCI Controller #2 (rev 03)
00:1d.7 USB Controller: Intel Corporation 82801DB/DBM (ICH4/ICH4-M) USB2 EHCI Controller (rev 03)
00:1e.0 PCI bridge: Intel Corporation 82801 Mobile PCI Bridge (rev 83)
00:1f.0 ISA bridge: Intel Corporation 82801DBM (ICH4-M) LPC Interface Bridge (rev 03)
00:1f.1 IDE interface: Intel Corporation 82801DBM (ICH4-M) IDE Controller (rev 03)
00:1f.5 Multimedia audio controller: Intel Corporation 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) AC'97 Audio Controller (rev 03)
00:1f.6 Modem: Intel Corporation 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) AC'97 Modem Controller (rev 03)
01:07.0 FireWire (IEEE 1394): Texas Instruments TSB43AB22/A IEEE-1394a-2000 Controller (PHY/Link)
01:08.0 Ethernet controller: Intel Corporation 82801DB PRO/100 VE (MOB) Ethernet Controller (rev 83)
01:0a.0 Network controller: Intel Corporation PRO/Wireless LAN 2100 3B Mini PCI Adapter (rev 04)
01:0b.0 CardBus bridge: Toshiba America Info Systems ToPIC100 PCI to Cardbus Bridge with ZV Support (rev 32)
01:0b.1 CardBus bridge: Toshiba America Info Systems ToPIC100 PCI to Cardbus Bridge with ZV Support (rev 32)
01:0d.0 System peripheral: Toshiba America Info Systems SD TypA Controller (rev 03)

Logfile from last working suspend, but no logs from resume available:
>> cat /var/log/pm-suspend.log
Mon Sep 29 23:58:51 CEST 2008: running suspend hooks.
===== Mon Sep 29 23:58:51 CEST 2008: running hook: /usr/lib/pm-utils/sleep.d/00clear =====
===== Mon Sep 29 23:58:52 CEST 2008: running hook: /usr/lib/pm-utils/sleep.d/05led =====
===== Mon Sep 29 23:58:52 CEST 2008: running hook: /usr/lib/pm-utils/sleep.d/10NetworkManager =====
===== Mon Sep 29 23:58:52 CEST 2008: running hook: /usr/lib/pm-utils/sleep.d/20video =====
kernel.acpi_video_flags = 0
===== Mon Sep 29 23:58:52 CEST 2008: running hook: /usr/lib/pm-utils/sleep.d/49bluetooth =====
===== Mon Sep 29 23:58:52 CEST 2008: running hook: /usr/lib/pm-utils/sleep.d/50modules =====
===== Mon Sep 29 23:58:52 CEST 2008: running hook: /usr/lib/pm-utils/sleep.d/90clock =====
===== Mon Sep 29 23:58:53 CEST 2008: running hook: /usr/lib/pm-utils/sleep.d/94cpufreq =====
===== Mon Sep 29 23:58:53 CEST 2008: running hook: /usr/lib/pm-utils/sleep.d/95led =====
===== Mon Sep 29 23:58:53 CEST 2008: running hook: /usr/lib/pm-utils/sleep.d/99video =====
===== Mon Sep 29 23:58:53 CEST 2008: running hook: /etc/pm/sleep.d/999dvbt =====
Mon Sep 29 23:58:53 CEST 2008: done running suspend hooks.

And nothing valuable in /var/log/messages
Sep 29 23:19:59 mythtv -- MARK --
Sep 29 23:39:59 mythtv -- MARK --
Sep 29 23:58:52 mythtv kernel: [22991.497758] cx88/2: unregistering cx8802 driver, type: dvb access: shared
Sep 29 23:58:52 mythtv kernel: [22991.497766] cx88[0]/2: subsystem: 0070:9002, board: Hauppauge Nova-T DVB-T [card=18]
Sep 29 23:58:52 mythtv kernel: [22991.499209] ACPI: PCI interrupt for device 0000:04:02.2 disabled
Sep 29 23:58:52 mythtv kernel: [22991.765319] ACPI: PCI interrupt for device 0000:01:00.0 disabled
(I stop mythbackend and unload the cx88 modules before suspending the PC and reload the modules after resume. Elseway, the tuner will not work properly)

>> cat /etc/default/acpi-support
# Comment the next line to disable ACPI suspend to RAM
ACPI_SLEEP=true

# Comment the next line to disable suspend to disk
ACPI_HIBERNATE=true

# Change the following to "standby" to use ACPI S1 sleep, rather than S3.
# This will save less power, but may work on more machines
ACPI_SLEEP_MODE=standby

# Add modules to this list to have them removed before suspend and reloaded
# on resume. An example would be MODULES="em8300 yenta_socket"
#
# Note that network cards and USB controllers will automatically be unloaded
# unless they're listed in MODULES_WHITELIST
MODULES="cx88_dvb"

# Add modules to this list to leave them in the kernel over suspend/resume
MODULES_WHITELIST=""
#r8169"

# Should we save and restore state using the VESA BIOS Extensions?
#SAVE_VBE_STATE=true

# The file that we use to save the vbestate
#VBESTATE=/var/lib/acpi-support/vbestate

# Should we attempt to warm-boot the video hardware on resume?
#POST_VIDEO=true

# Save and restore video state?
#SAVE_VIDEO_PCI_STATE=true

# Should we switch the screen off with DPMS on suspend?
#USE_DPMS=true

# Use Radeontool to switch the screen off? Seems to be needed on some machines
# RADEON_LIGHT=true

# Uncomment the next line to switch away from X and back again after resume.
# This is needed for some hardware, but should be unnecessary on most.
# DOUBLE_CONSOLE_SWITCH=true

# Set the following to "platform" if you want to use ACPI to shut down
# your machine on hibernation
HIBERNATE_MODE=shutdown

# Comment this out to disable screen locking on resume
#LOCK_SCREEN=true

# Uncomment this line to have DMA disabled before suspend and reenabled
# afterwards
DISABLE_DMA=true

# Uncomment this line to attempt to reset the drive on resume. This seems
# to be needed for some Sonys
# RESET_DRIVE=true

# Add services to this list to stop them before suspend and restart them in
# the resume process.
STOP_SERVICES=" "

# Restart Infra Red services on resume - off by default as it crashes some
# machines
RESTART_IRDA=false

# Switch to laptop-mode on battery power - off by default as it causes odd
# hangs on some machines
ENABLE_LAPTOP_MODE=false

# Spindown time on battery
SPINDOWN_TIME=12

Is there any way to get better debug info from the failed resume?