Error: The user class is either missing or invalid.

Problem

An error message is displayed to the report consumer when attempting to run an Impromptu Web Reports ( IWR ) report against a Microsoft Access database residing on a computer other than the IWR server. Error Message - Application Error The following error has occurred: The user class is either missing or invalid. The report runs to completion in Impromptu client and through the Impserver interactively. The following error messages are written to the NT Application Event log - WOTTDAHLGREJ2, 3228(cfc), 2002/10/21 11:08:49.584; [Microsoft][ODBC Microsoft Access Driver] The Microsoft Jet database engine cannot open the file '(unknown)'. It is already opened exclusively by another user, or you need permission to view its data. WOTTDAHLGREJ2, 3228(cfc), 2002/10/21 11:08:49.584; Logon error while connecting the database. Report: \\?\C:\Program Files\Cognos\cer2\ReportSet\apps\ReportName.imr WOTTDAHLGREJ2, 3228(cfc), 2002/10/21 11:08:49.584; Error: 0, Generic; Process ID: 3228; Thread: 3324; Host: WOTTDAHLGREJ2; Text: Failed to change user class.; BackTrace Info: 1. File Name: Y:\src\impromptu\ImpromptuServer\app.exe\ole.lib\APPAUTO.CPP; Line#:8736; Desc.:Failed to change user class.; SWID=20021021110850275WOTTDAHLGREJ2PID3872TID3268 - WOTTDAHLGREJ2, 3932(218), 2002/10/21 11:08:50.495; Error: 0, Generic; Process ID: 3932; Thread: 536; Host: WOTTDAHLGREJ2; Text: The following error was sent to the Consumer. Error number: 37 .