I had an issue with deDE locale as well (assuming we both have WoW from the same download)
Go into worldserver.conf and change DBC.Locale = 3 to DBC.Locale = 0
This stops it from checking the German DBCs and uses the English ones instead enUS assuming those are the ones you're editing.
Don't know if this fixes the issue, still messing around with it myself.
EDIT: It did fix some errors I was having with streaming, but I still can't teleport to my new area.