Stubborn lock(?) with psqlODBC+MSAccess

I'm running PG7.2.1 on RedHat 7.2 with the latest psqlODBC as my
database backend, with a Win98SE box running Access97 as the front
end.

I UPDATEd a record from the linux box in psql.

Now, when I attempt to UPDATE that same record from MSAccess, I get a
"Write lock" notice with no choice but to "Copy Changes to Clipboard"
or "Drop Changes." (the "save changes" button is grayed out.)

I have tried multiple stops/restarts of postmaster, a VACUUM, and a
review of /tmp for stray lockfiles (there were none) and still this
behavior in Access, for this one particular record, persists.

However, I can UPDATE this record as much as I like from psql and in
pgAdmin.

----

Possibly related bad behavior:
Within access, if I try to edit the same record multiple times in the
same connect session, the first keystroke of the second and subsequent
edits yields the dialog:

"The data has changed. Another user edited this record and saved the
changes before you attempted to save your changes. Re-edit the
record."

After which I can make my edit without incident.