That looks fine.
Are you comfortable at all at looking in the database? There is the prefixset table where you should see your prefixsetid and then there is the prefix table which should show your prefixid (1) and prefixsetid (??) . The prefixes are actually stored as phrases. You should have a phrase in the Thread Prefixes phrase group for your reports group and then two global phrases for each prefix named "prefix_id_title_plain" and "prefix_id_title_rich" with id replaced with your id (in your one above, the id is "1") so look for "prefix_1_title_plain" and "prefix_1_title_rich" and make sure they exist.
|