Don't try to get into the castle before you have an invitation (by tossing a teleporter stone in), and it is very unlikely you will run into a serious story problem that doesn't have a fix. Other than that, it is unlikely you will encounter more than minor problems (knock on wood). I did much of the game under 1.29, and only installed the hotfix because I broke Finnigan's lockpicks (the hotfix/patch fixes that bug and restores them if they were broken by using Lockpick). There are a couple quests that might be partially broken if you do things in an unexpected order, but I didn't break any myself.