Affects Version/s: 12.5, 19.0, 20.0
Environment:Sakai nightlies 12/19/trunk
1. Create a site with 2 weighted gb categories with no actual gb items in them
2. Create an assignment and link it to one of the categories in the GB
3. Create a second site with Assignments and GB tools
4. Use Site Import->Replace to bring over Assignments and GB tools
5. Go to Assignments tool and edit the draft assignment
6. In the dropdown for grading, select the category for the item to be placed in.
7. Press save
The page now reloads an does not save. The attached stack trace is printed in the tomcat logs.