Put to items together (without giving a special name to the new item) and you see the XP-price you will have to pay.

THE BUG IS:
If you're playing with german language for example you will have to pay 7 more XP-levels then it has been shown in the information.

THE REASON FOR THE BUG IS:
The server thinks that you want to give your item a new name, because the item has an english name, but in the description field where you COULD give the item a name is the german name. --> 7 XP-levels more.

WORKAROUNDS TILL BUGFIXING:
A) Change to english language to use the anvil.
B) Give your item the "english name".

THANKS TO:
Lorgren, Ingelfingen and espacially TriPhoenix
from kadcon.de
for testing and detecting.

http://forum.kadcon.de/index.php?page=Thread&threadID=5697