FATAL: catalog is missing attributes

Hi,

I was trying to make a dump from a database in postgresql 7.4.2-1. I was
enable to do so because of a cache lookup problem.
To solve it, I enter the database as superuser and execute VACUUM ALL.
This was even worse than the previous error. Right now I cannot enter
the database neither make a dump. When I execute a command such as "psql
-U postgres center-01" I get the error:
psql: FATAL:  catalog is missing 10 attribute(s) for relid 1262

Since the backup it too old, I must enter this production DB and extract
the data but it is unavailable. I look at similar threads in the
archives but all the solutions assume that it is possible to access the
database and this is not my case.

Can anyone help on this?
Thanks in advance
Bruno Cortes