recordset not updateable

I am using rh 5.2, postgres 6.4.2, linking to postgres with access97 and
odbc driver. I can create a simple table, link to it, open it, and access
tell me that "this recordset is not updateable". However, I have created
many other tables in the same fashion and even much more complex and they
are just fine. Any idea what could be going on? This just started
happening today. Most of the tables I created over the past few weeks are
working fine (I met one exception which has led me to create some test
tables and link to them). BTW, I can update the table directly in psql on
the server itself with no problem, so it must be odbc or access. But why
do the other tables still work just fine? HELP!!!! Where can I look??

JT