Random panics on FreeeBSD 6.0

[Matthew Navarre]

I've got an AMD Sempron machine running FreeBSD 6.0 that's been  
experiencing random panics while trying to build world. In fact it  
just paniced now, with no activity.

The panic message is TPTE at 0xbfc20624 IS ZERO @ VA 08100000
bad pte

This started last night while I was portupgrading ruby and I got  
random apps segfaulting, mostly gcc, so I suspected bad memory. I  
installed new memory today, tried to buildworld. And *BAM* panic: bad  
pte

I'm still guessing that this is a hardware problem, and not software  
but I'm not sure. If anyone can give me a clue I'd appreciate it.

Machine details:
AMD Sempron
ECS K8M800-M2 mainboard
1 GB Kingston PC-3200.

Thanks,
Matt