#3 - Aug. 16, 2010, 6:18 a.m.
Couple things you can try, Coman.
First, I'd do a reset UI. If there is some type of conflict or corruption, that can help.
If that doesn't seem to allow you access to this character, place a petition on another character you can log in with describing the issue and that character can be moved. If it's a location issue, that could resolve it.
To do a full reset UI, you will want to save your addons in another spot if you wish to preserve them.
Then rename/delete or move your WTF, Cache and Interface folders while WoW is shutdown. Reboot your system.
Note, if you are running Vista make sure your permissions are set so it does not undo your changes.
More detailed instructions for different operating systems, including Macs are here.
http://us.blizzard.com/support/article.xml?articleId=18761&searchQuery=reset%20UI&pageNumber=1