backend stalls

Hi

I'm tearing my hair out here, the backend seems to randomly decide to stall
and not serve any more queries (processes are listed as waiting).

It happens on all sorts of queries (including CREATE TABLE and CREATE INDEX).

I have completely uninstalled and deleted the whole installation and
reinstalled - only to have it do it again mid way through entering the SQL to
rebuild my database (not a big one ~25 tables, and no rows to speak of -
havent got that far yet).

I was thinking corrupted tables - or corrupt system catalog, but even
vacuumdb stalls as well...

Any help would be appreciated, I have so much work to do and I cant do
anything without the database working :(

My install is Postgres 7.0.3-8 from the RedHat RPMs runing on RH7.1

I know I havent given much specific information, I dont really know where to
start.  What its doing at this very minute is hanging on an insert into a
freshly created table on an installation thats only existed for 30 minutes
and only just had all the tables created.

Thanks

Shane