There is a small bug with the userlevels. The issue comes when you register on the blog with a different capitalization than you actual game name is. While you were added you to a usergroup before through the website with the same nickname as you registered there, the new version of the permissions plugin checks for your minecraft game-nickname and is picky there on the capitalization. If the spelling is different, it cannot find you and automatically registers you as a “guest”.
If that happens, send me a message in the forum and I will fix it. Please do not re-apply for a lot or similar stuff.