Hello Tom,
I just got a mail that suggested your answer as the right one and I suddenly realized that I had this still on my "ToDo list" and therefore I had not answered or flagged your post as the answer to the problem.
Thank you very much and shame on me! It indeed is the simple solution to my problem,
Is there a list of reserved names in a documentation somewhere? I could not find such a list in the TI users guide by scanning through.
Thanks again and sorry I didn't reply sooner,
Jan