Hi, Frank.
We've had the some trouble recently and I paid my attention to the fact that the table USVART is language dependent. If a data element is a custom one (z*) and was created inaccurately, then there could be some troubles while using standard program PFCG_ORGFIELD_CREATE as it won't be able to add a field to USVAR & USVART.
We've solved our problem by recreating data element.