Was a lisp image problem ... Had to restart my lisp session. Now things are working. It wasn't a cells problem ...
Note: I changed the loop stuff into a simple (c? (length (^kids))) because I have to count everythíng in there. Now a task can have a task instance as a kid.
hmm - that makes a task tree or, in other words, a /program/ ! <g> Cells is just beautiful. I even don't have to see what part of the "program" has to be re-executed because the "program" or any content (= variables) have been changed...
Frank