Acpi related problem?

Hi all,
on my destkop power off sometime works, sometime doesn't work (on
screen remains 'powering down using ACPI')

I imported the ACPI-20070126 patch.
It looks fine (even it has a warning message), but nothing changes .
How can I solve or better investigate this issue?

Dmesg's acpi related:

ACPI: RSDP _at_ 0x0xf8cb0/0x0014 (v  0 ACPIAM)
ACPI: RSDT _at_ 0x0x3ffb0000/0x0038 (v  1 A_M_I  OEMRSDT  0x12000620 MSFT
0x00000097)
ACPI: FACP _at_ 0x0x3ffb0200/0x0084 (v  2 A_M_I  OEMFACP  0x12000620 MSFT
0x00000097)
ACPI: DSDT _at_ 0x0x3ffb0440/0x5095 (v  1  CRXR2 CRXR2167 0x00000167 INTL
0x02002026)
ACPI: FACS _at_ 0x0x3ffc0000/0x0040
ACPI: APIC _at_ 0x0x3ffb0390/0x006C (v  1 A_M_I  OEMAPIC  0x12000620 MSFT
0x00000097)
ACPI: MCFG _at_ 0x0x3ffb0400/0x003C (v  1 A_M_I  OEMMCFG  0x12000620 MSFT
0x00000097)
ACPI: OEMB _at_ 0x0x3ffc0040/0x0046 (v  1 A_M_I  AMI_OEM  0x12000620 MSFT
0x00000097)
ACPI: HPET _at_ 0x0x3ffb54e0/0x0038 (v  1 A_M_I  OEMHPET  0x12000620 MSFT
0x00000097)
ioapic0 <Version 2.0> irqs 0-23 on motherboard
kbd1 at kbdmux0
ichwd module loaded
acpi0: <A_M_I OEMRSDT> on motherboard
acpi0: [ITHREAD]
acpi0: Power Button (fixed)
Timecounter "ACPI-fast" frequency 3579545 Hz quality 1000
acpi_timer0: <24-bit timer at 3.579545MHz> port 0x808-0x80b on acpi0
cpu0: <ACPI CPU> on acpi0
ACPI Warning (tbutils-0243): Incorrect checksum in table [OEMB] -  3B,
should be 2E [20070126]

Thanks
-- 
Diego Depaoli