Avadon: The Black Fortress
If you cannot level up because you have no way of spending your skill points, here is something that might help.
When you retrain your character I believe you get the amount of points you are supposed to have on your current level, and not the amount that you actually had altogether. That is, if you have gotten 10 from leveling up, got another 20 with the trainer, then respec, you will have 10, not 30.
You can respec with Leala, who is found in the Beraza Woods, on the east side (this is within Kellemderiel).
Also, if you have not gotten access there yet, there is a simple character editor that allows you to retrain in Redbeard's tower to which you have access to for almost the entire game. There is a thread about this editor here: Link
If you do manage to solve your problem with either of the methods, please post here, so that others will know.
I believe you get 58 skill points throughout the game, and you need 101 to get all skills to max level, so it is probably safe to use the trainer twice (netting you 98 points, landing you 3 short of maxing out everything).
[Edited by WinuX, 7/2/2012 2:30:46 PM]
[Edited by WinuX, 2/20/2013 3:56:06 PM]
[Edited by WinuX, 2/20/2013 3:55:24 PM]
Replaced link in original post as well.
[Edited by WinuX, 2/20/2013 3:56:29 PM]