Well, I finished this one, and I found the problem in dungeon 7 as mentioned above. Checking other websites, I found that the quest has been updated, but the link in this thread wasn't (It points to the old version where dungeon 7 couldn't be finished). Fortunately for scootaloo, I found the update, and proceeded to finish the quest.

The quest, as a whole, is a fairly good one, though nothing I haven't seen before in any of the new creatures, with the exception of the ones that cause a reason for the cross. There was only one major bug that I encountered in the updated map: In level 9, I couldn't return from the silver arrows. The pushable block used to get into the room from the one south of it couldn't be pushed from the other side. I was out of bombs at that point, so if there is a bombable wall in the arrow screen, I couldn't find it. Anyway, that forced a quit-continue to finish the quest.
The update's music was interesting- the overworld music has got a good adventuring feel, but I thought the level 9 music was way too light.
I don't know if it was intentional, but I didn't need one of the keys in level 8- In fact, I had already explored both sides of one of the locked doors before I found the key for it (Other keys that I had found could have been used on that door, bu I chose other paths). As a result, I found Ganon very quickly (of course, with no silver arrows yet, I didn't go in. I would suggest putting in a second locked door in the Ganon-path, so that even if a player has that extra key, he cannot get to gannon without the magic key (or, of course, buying an extra one from a shop).
One other problem was that there are a few creatures with upgrades (Zol, Pol's Voice) where the upgrade doesn't look any different- though in the case of the Pol's Voice, the upgraded ones move faster. I think some distinction should have been made- particularly when immunities are changed.

So, with the contest in it late stages, I don't have much more to say here, so I'll just give my rating- 3.42 / 5.