You should try deleting the cache file to see if that helps you to get past the error. There are instructions for doing this in the document here:
common_installation_issues.pdf
If this does not work to resolve the problem then there may be a corruption of your configuration folder. To undo that you would need to rename the configuration folder, here is a post with steps you can take for that:
showpost.php?p=12293&postcount=2