Error message: Ambiguous column (<column_name>). (-324) If you encounter the Informix-specific "Ambiguous column" errors, take the following action: Make sure the problem query executes successfully in the Informix native dbaccess program. Place backslashes in front of any underscores that appear in the query, to escape those underscores. Use pass-through queries with fully qualified field names when Microsoft Access is involved. If using Multi-Tier, make the following change to the Broker Rulebook and test: Log in to the computer that hosts your OpenLink server components. Open the active Rulebook (e.g., oplrqb.ini) in a text editor. Locate the relevant [Environment ___] section that corresponds to the acgtive database agent, e.g., [Environment INFORMIX2000]. Set the following parameter: DELIMIDENT = Y Save your changes and exit the file. Restart your Request Broker. Other known possible causes of this problem include the use of ADO or Microsoft Access '97.