It looks like my box is suffering from the same bug, although in Ubuntu 8.04.1 (2.6.24-19). My system also freezes at random apparently, most of the time leaving no messages in the logs whatsoever. However, I found a same 'Eeek' message in the logs very recently:

Aug 12 11:32:30 quadpc kernel: [101268.516775] Eeek! page_mapcount(page) went negative! (-1)

Please see below for some additional information (and messages attached).

uname -a: Linux quadpc 2.6.24-19-generic #1 SMP Fri Jul 11 23:41:49 UTC 2008 i686 GNU/Linux

Sysinfo output:

System information report, generated by Sysinfo: 13/08/2008 10:14:25 PM
http://sourceforge.net/projects/gsysinfo

SYSTEM INFORMATION
	Running Ubuntu Linux, the Ubuntu 8.04 (hardy) release.
	GNOME: 2.22.3 (Ubuntu 2008-07-09)
	Kernel version: 2.6.24-19-generic (#1 SMP Fri Jul 11 23:41:49 UTC 2008)
	GCC: 4.2.3 (i486-linux-gnu)
	Xorg: unknown (13 June 2008  01:08:21AM) (13 June 2008  01:08:21AM)
	Hostname: quadpc
	Uptime: 0 days 2 h 9 min

CPU INFORMATION
	GenuineIntel, Intel(R) Core(TM)2 Quad CPU    Q6600  @ 2.40GHz
	Number of CPUs: 4
	CPU clock currently at 1596.000 MHz with 4096 KB cache
	Numbering: family(6) model(15) stepping(11)
	Bogomips: 4814.38
	Flags: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx lm constant_tsc arch_perfmon pebs bts pni monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr lahf_lm

MEMORY INFORMATION
	Total memory: 2026 MB
	Total swap: 4769 MB

STORAGE INFORMATION
	SCSI device -  scsi0
		Vendor:  ATA      
		Model:  WDC WD3200AAKS-0 
	SCSI device -  scsi7
		Vendor:  HL-DT-ST 
		Model:  DVD-RAM GSA-H55L 
	SCSI device -  scsi7
		Vendor:  ATA      
		Model:  SAMSUNG SP1203N  
	SCSI device -  scsi4
		Vendor:  ST350063 
		Model:  0A               

HARDWARE INFORMATION
MOTHERBOARD
	Host bridge
		Intel Corporation 82G33/G31/P35/P31 Express DRAM Controller (rev 02)
		Subsystem: ASUSTeK Computer Inc. Unknown device 8276
	PCI bridge(s)
		Intel Corporation 82G33/G31/P35/P31 Express PCI Express Root Port (rev 02) (prog-if 00 [Normal decode])
		Intel Corporation 82801I (ICH9 Family) PCI Express Port 1 (rev 02) (prog-if 00 [Normal decode])
		Intel Corporation 82801I (ICH9 Family) PCI Express Port 5 (rev 02) (prog-if 00 [Normal decode])
		Intel Corporation 82801I (ICH9 Family) PCI Express Port 6 (rev 02) (prog-if 00 [Normal decode])
	USB controller(s)
		Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #4 (rev 02) (prog-if 00 [UHCI])
		Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #5 (rev 02) (prog-if 00 [UHCI])
		Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #6 (rev 02) (prog-if 00 [UHCI])
		Intel Corporation 82801I (ICH9 Family) USB2 EHCI Controller #2 (rev 02) (prog-if 20 [EHCI])
		Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #1 (rev 02) (prog-if 00 [UHCI])

GRAPHIC CARD

SOUND CARD
	Multimedia controller
		Intel Corporation 82801I (ICH9 Family) HD Audio Controller (rev 02)
		Subsystem: ASUSTeK Computer Inc. Unknown device 829f

NETWORK

NVIDIA GRAPHIC CARD INFORMATION
	Model name: GeForce 8600 GTS
	Card Type: PCI-E 
	Video RAM: unknown
	GPU Frequency: unknown
	Driver version: NVIDIA UNIX x86 Kernel Module  169.12  Thu Feb 14 17:53:07 PST 2008