invalid page header problem

Hi!

We currently have a serious problem with our postgres-DB!

We are using postgres now for some time and lately we expericened
that tables were corrupted on the 7.3.2 Database. After recreating
the Tables by copying the contents to a save-table and then dropping
and recreating the original table we could at least help that
withourt losing data.

We then decided it couldn't hurt to upgrade to 7.4 and hope that the
problems were solved, but they weren't they just changed. In fact
now we are losing data because we cannot select * from the table
anymore without getting the new Error.

At current we get the Error
"invalid page header in block 2617 of relation "xxxx"; zeroing out
page"

We actually tried to find out what the problem was and the table was
fine till some tuple crashed with the bug. We then made a
pg_filedump, and added "zero_damaged_pages" to the config so that we
could make a clean dump ... since the table is mainly used for
high-traffic messaging it was ok to maybe lose the one block of
messages by zeroing them out.

The problem is, that this keeps happening and we don't know why ...
Actually this is a fresh installation of postgres 7.4 and a fresh
initialized database with a dump inserted with psql -e < dumpfile,
showing the problems after just 12 hours of work.

The only thing changed before compiling the postgres is the
INDEX_MAX_ARGS to make it possible to send more than 32 parameters
to a function which work and always worked fine because we do inserts
and updates encapsulated in stored procedures.

We also tried to check the HDD and could not find any evidence of
corruption or problems on the HDD-Side ...

Any help with how to find out more WHY this problem keeps showing up
and how to fix this is appreciated, because the only thing we see is
that perhaps some piece of hardware may be corrupt and we have to
change that, but before spending a lot of money on new hardware i'd
like to rule out that this is a software-problem!

Regards ... Manuel ...