Wordpress 2.5 RC2 = Not Cool!

This morning i installed the new Wordpress 2.5 RC after testing it on my dev install with out any issues. This was not the case when i decided to upgrade Studio Lounge. I got a fetal error from a taxonomy.php file and every thing broke, the front end as well as the back end, i was forced to revert back to Wordpress 2.3.3. I have logged the error and have no idea why it happened, i only how the issue is fixed by the time it is released.