"Key Column Information Is Insufficient..." Error Even With A PK

I am using an .adp Access file and I am having trouble editing records through it. My form displays the contains of a table one record at a time. When I try to edit one of the fields of the record, I get the following error after selecting Records>>Refresh or when I try to navigate to the next record:

Key column information is insufficient or incorrect. Too many rows were affected by update.

Despite this error message, the modification is written to the database (I checked with SQL server management studio).

If again try to refresh or navigate away from that record--even if I have not made any additional edits--I get an additional error before the first one:

This record has been changed by another user since you started editing it. If you save the record, you will overwrite the changes the other user made....(some boring junk)

Once these errors have started, they continue whenever I try to navigate to the next record even though change has already been written to the database. I end up stuck on that record until I restart the app.

How do I get rid of these error messages?

I have read online about not having a primary key on your table will cause this error, but I already have already added a primary key to the table.

If it matters, the field I am attempting to edit is not a part of the primary key.

If it matters, when I check the properties of the form, I see:
Record Source is set to the table's name,
there is a "Filter" applied,
there is a "Order By",
the "Recordset Type" is set to "Updatable Snapshot",
"Server Filter By Form" is set to No, and
"Allow Filters", "Allow Edits", "Allow Deletions", and "Allow Additions" are all Yes.

Details:
OS: MS XP Version 2002, 5.1.2600 Service Pack 2 Build 2600
Access: Access 2003 (11.6566.8122) SP2
Database: Microsoft SQL Server 2005

Thanks,
Matt