stability issues

Hi,

I'm running a PostgreSQL 8.1.9 server on Debian etch (default installation,
w/ PostGIS from Debian repositories).
The machine has double Xeon 5130, 4 GB of DDR2 ECC Reg. RAM and a
two-sata-disc Raid 0 cluster. I don't know the brand of the memory nor the
HDDs. The Riad controller is a 3Ware 8006-2.

Lately i've been confronted by some failures in several PostgreSQL clusters.
3 weeks ago a cluster crashed when i was reindexing it, beond my repair.
Last week we've been getting Toast warnings and shared index problems on
another cluster. I solved the shared index issue, but the Toast trouble
remained, in more than one database on that cluster. I dumped the databases,
created another cluster and shut the troubled one down. (problems were
solved).
I've asked our provider to do a filesystem check, (e2fsck -f /dev/sda1)
which indicated that "there's nothing wrong with the filesystem".

This doesn't feel right.
Is there anything else i should check?

thx,

WBL