This is a general error that indicates indicates that there is an error in a table or object definition within the database catalog, or an inconsistency between the database catalog and the actual tables. The error message displayed will provide additional detail about the specific instance of the error.
This error can be caused by numerous events such as a power outage while data is being written, a failing hard drive, anti-virus software, or even automatic backup software such as Carbonite (http://support.1000years.com/kb/a22/carbonite-online-backups.aspx).
If the error is minor, it can be repaired using the Repair Tables option of the "Options - Batch Processing" function with the "Repair Tables" option selected.
If the error is not resolved by running the "Repair Tables" option of the batch processing, the database is damaged beyond repair and you will need to restore from a backup taken prior to the onset of the issue.