ERROR: cache lookup failed for relation 438095645

Hey list,
I am getting this error "ERROR: cache lookup failed for relation
438095645" when i try to run "drop table
pl_inventory_analyzer_files_table ;" from psql on the database server.
I've already REINDEX'd the database system tables, and all the indexes
on that table, and on all the indexes on any tables referenced by
foreign keys. OS and Version info below, more info available upon
request. Does anyone have any suggestions on how to fix this?

Thanks,
Joe

select version();
version
--------------------------------------------------------------------------------------------
PostgreSQL 7.4.6 on x86_64-unknown-linux-gnu, compiled by GCC gcc (GCC)
3.2.2 (SuSE Linux)
(1 row)

uname -a
Linux mammon 2.4.21-273-smp #1 SMP Mon Jan 17 12:31:48 UTC 2005 x86_64
unknown