Problems with acpi

[Konrad Neuwirth <konrad%fimsch.net@localhost>]

Hello,

we are currently experiencing very, very strange behaviours out of one  
of our machines at a remote hosting location.  It keeps sporadically  
crashing entirely too often (say, twice a week), with roughly the  
following message:

uvm_fault(0xc0a0cbc0,0x33332000,1)->0xe
Kernel:supervisor trap page fault, code=0
Stopped in pid 2.1 (sysmon) at netbsd:AcpiNsMapHandleToNode 
+0x16:        cmbp$0xf,0(%eax)
db>

The kernel also keeps complaining about unknown power types -- we've  
had the following messages logged since the reboot this morning.

unknown power type: -1071846480
unknown power type: -1037142656
unknown power type: -1037142608
unknown power type: 16387
unknown power type: 16387
unknown power type: -1030693888

So I know acpi is a strange creature, but what can be causing /this/?   
And would it be worth a try to actually move back to apm on this  
machine?

Puzzled
 Konrad