This error is displayed if there is an error reading, writing, or validating a table.
If this error occurs consistently, every time the same table is accessed, the table is damaged. If the damage is minor, it can be repaired using the Repair Tables option of the "Options - Batch Processing" function. If the damage cannot be repaired, you will need to restore from a recent backup taken before the onset of the issue.
If the error is intermittent, this is an indication that something is blocking proper access to the table. One known common cause of this error is "Live" backup software programs such as Carbonite. Please refer to the following article on how to properly configure your live backup solution for use with Atrex: http://support.1000years.com/kb/a22/carbonite-online-backups.aspx