Can't select my weapon!

[Hackebrät]

I reached Level 20 and so I bought Rumen Sword(Lv.20 Fighter).
I selected the Titel Clever Fighter in order to take the weapon but nothing happened.
Now i am Level 21 an it almost doesn't work.
What's the problem?Thank you for your answers.

[Tamlinari]

You cannot use any level 20 weapons, armor, jewelery or items until you pass the Shadow Quest.

Go see Master Marty at the fountain in Elderine and get the quest.
He will ask you to take a letter to Skill Master Ruby in Roumin.
Ruby will give you a letter to take back to Master Marty.
After that he will send you to Grand Master Sean in Forest of Myst by the lake.
Grand Master Sean will send you to look for the "Dungeon Key".
Someone else can help guide you through the Shadow Quest.
Pass the Quest and you get your official Clever Fighter title and your choice of a new level 20 weapon for free.

[Hackebrät]

Ok thank you

[Trebori]

http://www.fiestafan.com/wiki/Level_20_Job_Change