"Runtime error 3343 unrecognized database format" This error refers to the frxque32.mdb file and occurs when launching the Queue Monitor.
The frxque32.mdb file has been corrupted.
Please Note: Scheduled reports are stored in the FRx queue database. If reports have been scheduled, the schedule records will be lost when a new queue database is created. Reports must be re-scheduled after completing these steps. Locate the frxque32.mdb file in the FRx Queue directory (typically the same as the FRx SysData directory). Rename frxque32.mdb. (For example, frxque32.mdb.old). The Report Server will automatically create a new queue database from the .TPL if one is not found.