If you are getting this error after deleting the cache file then there might be a problem with your configuration. For reference here is a link to the steps for deleting the cache file:
common_installation_issues.pdf
If the configuration is corrupted you will need to go through the steps listed here to resolve the issue:
showpost.php?p=12293&postcount=2
If you continue to have this problem after doing this please post back and let us know.