I was doing an upgrade when I got this error. There is a file named UPGRADE in the zip that has directions for upgrading. I skipped over step 4:

4. Once installed you MUST recreate your SQL tables. You will lose all existing messages and users. To recreate the tables, go to Setup->SQL Server and select "Create new tables and overwrite existing data".

I did that and it solved my problem.

Hope that helps.
~Charlie