Hello spick!
There are a lot of user-made Mods, with both new items and/or content. Some of them are pretty good, but some of them are just minor(e.g. Look at the neato sword!).
Are you directing the "glitch" part at me, or at someone else? If it is me, then the glitch would be that if the power went out, or the game crashed, then the quest files would get corrupted. Since they are on a different folder than every other part of the game, nothing else was affected. Your character(with all the items and stats intact), the Teleport areas opened, and last fountain visited, were all intact. The way to get around this is to go into the folder(which I cannot recall offhand, but I know that they mention it as a sticky over there) and copy over the quest files from a time before the "incident" occured.
Just make sure that you make a back-up folder of the quest files for two reasons.
1. You might copy over a file too far, and you would have to walk all of that distance again.
2. The more you copy the files over into the backup folder, the easier it is to make sure that you don't have to do parts of the game over in case of catastrophe.
Sorry if I am not making a whole lot of sense. It has been a fair while since I've played.
What is the hardest creature that you've faced so far?