When creating a new test definition and selecting an object, the error "List index out of bounds" pops up. This is only happening for a particular database schema. When logging in using a different schema, the same objects can be tested without issue.
Repository objects which were previously installed on the problematic schema co-exists with the correct repository owner's objects.
Remove the Code Tester repository objects from the problematic schema. Be sure that you only have these objects installed on the repository owner which you have selected during installation. Please contact support for identifying and cleaning up these Code Tester objects.