ODBC connection stopped working.

I have a small (but growing) postgresql database that employees in the
office connect to with Access97.  I built the client application in Access
and distributed it, and it has been running perfectly for the past two
weeks or so.  The ODBC connection is set up to connect as the superuser
(postgres) with no password (and I have not added a password) (yeah,
insecure, but I'm working on a bigger database to replace it that will have
good security, and I'm on an internal network anyway).  Anyhow, some time
this morning, the datbase started rejecting connections from the clients,
saying "ERROR:  (tablename): Permission denied."  If I re-link the tables,
sometimes it will go back to working until I close the datbase and open it
again.  Here is a snippet from my log:

010821.10:55:15.935   [898] ERROR:  Relation 'msysconf' does not exist
010821.10:55:15.966   [898] ERROR:  client: Permission denied.
010821.10:58:01.806   [899] ERROR:  Relation 'msysconf' does not exist
010821.10:58:01.812   [899] ERROR:  client: Permission denied.
010821.10:58:28.961   [899] ERROR:  workorder: Permission denied.
010821.11:03:08.287   [936] ERROR:  Relation 'msysconf' does not exist
010821.11:03:20.907   [937] ERROR:  Relation 'msysconf' does not exist
010821.11:03:20.938   [937] ERROR:  employee: Permission denied.
010821.11:03:36.038   [939] ERROR:  Relation 'msysconf' does not exist

If I re-link the tables, sometimes only some of the tables will start
working again.  The ones that still do not work no longer produce the
'msysconf' lines in the log, but they do still give the 'Permission denied"
ones.

Does anyone know what the 'msysconf' errors are, or why the database would
be denying me connections as the superuser?  Please help!

Neal Lindsay