backing up corrupt database

My first post didn't work, so here goes again

I want to backup my database, which appears to be corrupt.  The projects
table is corrupt:
bash$ pg_dump devtest2
pg_dump: Attempt to lock table "projects" failed.  ERROR:  cannot find
attribute
 8 of relation projects

When I try to drop this corrupted table:
devtest2=# drop table projects;
ERROR:  cannot find attribute 8 of relation projects

How can I manually purge this table from the system tables so that I can run
a backup and then recreate the database?

Thanks

Terry Fielder
Network Engineer
Great Gulf Homes / Ashton Woods Homes
terry@greatgulfhomes.com