Hmmm. Funny... you should have three (5, 9, 13). Try taking to the guild leader about magic, spells, or even try choosing a spell. I know my paladin (12th) had the reverse... It said I had three slots but really only had two, so when I tried to choose a third spell it gave me this error message and reset my spellslots to the proper amount. Might work for you... that or call down the might of a GM and have them smite it.
-Mozzik
