The real trouble is that there is too much magic pooling in the area of old Thark. Jandari had planted some magic absorbing plants - but either they can not handle the trouble - or they are not being harvested well by the kobolds of the Dragon tribe.
The party met a manifestation of the Goddess of Magic - a dragon.
she granted them all a gift. She told them what the problem was, and calmed the trouble. The Arch was put back into it's manifested doorway.