Help: my table is corrupt!

Hello,

Can someone explain me how to repair a table?

If I execute a 'select * from <brokentable>'  in PSQL I get the next
error. A pg_dump export only partially export the broken table and
ends with the same error:

"Invalid memory alloc request size: 4294967290"

Note that this number is really close to 2^32.

I am running x86 Linux (Gentoo), with Postgresql 7.4.

This is what I tried to repair the table and all didn't work:

- Turning ZERO_DAMAGED_PAGES to true in postgresql.conf;
- Running REINDEX TABLE <brokentable>, and REINDEX DATABASE <thedb>
- Running VACUUM <brokentable>

This table contains arround 6 million records, and every record only
contains a few text, number and date attributes.

Queries/Exports on other tables works fine.

Is there a Postgresql Repair application which delete or repair
corrupt records?

Thanks in advance!

Jos