Typically the error 5000 is a data connection issue. I would suggest uninstall/reinstall if using the latest version, if not using 1.9.6.5, upgrade to resolve any issues.
When reporting an error such as this, please report the EXACT report being run so we can attempt to duplicate the issue. If this is occuring with all reports, attempt a repair on your database (File..Utilities..Repair) to see if that corrects the issue. If none of the above works, submit a support request and include a backup (File..Archive..Backup) of your data file for review.