Hello Michael,

You are right, exist 2 ways to fix it:

1. Open file: ftp://includes>>utils>>Category.php finc method: addUserCategory

find line:
PHP Code:
Only registered members can view the code. 
and replace to:
PHP Code:
Only registered members can view the code. 
save and check again.
________________________

2. Go to Admin Panel>>Languages find phrase by key: tmp_category_exists
and change '[category]' to '{category}'
this way will solve the problem also.