Just accept it, you dont actually have to go and do it; that is how I handle all the Festivals, accept it, then ditched the travel skill item that takes you there and forget all about it.
I guess i didn't point that out, when i accept the quest, it won't start (as it normally should), the questwindow just closes and the auto-quest-thing is still there. no matter what i click, it just won't start, cancel or disappear...
Have you tried cancelling it in the Quest Deed panel??
It does sound like you need SSG help. Good luck with that, of the 3 help requests I have submitted, only one has had a human response, and that was a week after I managed to sort it myself. The other two got an auto-response and silence.