Grand Master Tobias:
To become a Dark Wizard, the appropriate level and token are required. Your level must be at least 20 to qualify to change profession. You must also have a token that proves that you passed the Test of the Dark Wizard.
It seems that you admirably passed the Test of the Dark Wizard, but your level is not high enough. Level 20 or higher is required to change profession. I cannot allow you to change profession if your level is not sufficient, even if you have a token. Come back when you have raised your level.