BufTableDelete: BufferLookup table corrupted

Hi all !

I'm working with PostgreSQL 7.0.2, and I may have a little problem : my database 
seems to be corrupted.

When I connect to database (with psql, e.g.), I receive the message 'FATAL 1: 
BufTableDelete: BufferLookup table corrupted'.

If I insist, I can enter the database. But then, a couple of things doesn't work 
any more : \dt, to display tables, tells me 'ERROR: SearchSysCache: recursive 
use of cache 17'.

Statements seem to work, but I'm afraid the problem could extend.

So, is it so bad it seems to be ? Does someone has an idea how I can fix that 
problem without loosing all ?

Thanks in advance.

_____________
B. Carrupt