Listing tables - why doesn't it work?

I'm having a problem listing tables in my Postgres database.

I log in as superuser (i.e., psql rnw_hosted), and can describe the
tables individually, as \d error_type. There are a total of six tables
in the database, and I can access each one individually. But, when I do
a \dt, only one table is listed. Likewise, when I try to do a backup
using pg_dumpall, it complains because it can't find one of the tables.

Is this some kind of permissions problem?

Oh, and one more question: how can I query the system catalog tables?
The documentation mentions a syscat.source file in the src/tutorial
directory, but I haven't been able to find this directory anywhere on
the server.

We're running Postgres v.7.0 here.

Thanks,
--Walt Weaver
    Bozeman, Montana