You need to contact the author of the challenge checker script. Nobody else can fix the script for you from here.
In any case, this does not look like a change in the script as it was last updated in 2016. Probably something underlying changed like a sandbox, caches or something else. For the record, it runs fine for my name.
Finally, for challenge checkers, please, use the following forum as it is monitored more by people actually working on challenge checkers: https://project-gc.com/forum/index?3
As Seagnoid mentioned, it is probably one of your recent finds that is not correctly handled by the checker. The upper() function is used only on the cache owner names.