Uh... if you try to get level of an ability via a buff, it will return 1 or 0. In which 1 means it's present. According to the UMSWE GUI description anyway.
hm if you look at the buff field from the unholy frenzy ability, its 'BUhf' but the buff itself has 'Buhf' as id...
seems that there are two versions of the unholy frenzy buff (like purge), but theres only the 'Buhf' in my editor.
I know how to JASS, the problem is exactly what Hitchhiker said, the object editor says the buff id is 'Buhf' but the buff is actually 'BUhf' . Even the GUI trigger makes this mistake when converting the Buff Id