I updgraded from 1.9 to 2.0 becuase my hosting service no longer support MOODLE So I need to update it manually. However, when trying to grade work I get this error message. I can see how many assignments are submitted, but when I click assignments this is the error message I receive. While in 1.9 I recently received a "Nothing to Display" notice, upgraded to 2.0, and now I receive the below message.

Website is www.cpowerdesigns.com/theoc

Warning: mysqli::query() [mysqli.query]: (22003/1690): BIGINT UNSIGNED value is out of range in '(`cpowerdesigns_com_1`.`s`.`timemarked` - `cpowerdesigns_com_1`.`s`.`timemodified`)' in /home/cpowerde/cpowerdesigns.com/theoc/lib/dml/mysqli_native_moodle_database.php on line 758