ODBC Driver

Hello!! I have been using the "Openlink" ODBC driver to link my Informix 7 database to my Ms Access database (running on Windows 3.11). After we set it up ( with a few problems) and attached the tables, we can actually run queries on the information ( as long as the amount of data is not very large). My problem comes when I try to update a field on the database. When I try to do that, the database gives me the error: "The field is not updatable". I cannot enter new data or change the existing records ( and to me, not being able to update the records or enter new records defeats the purpose of having an ODBC driver) I haven't been able to find where the problem resides (would it be an MS ACCESS problem, an Informix problem or the ODBC driver problem?) Has anyone around here had this problem? I would definitely need some help!! Thanks --