Hello Oliver,

had just a very quick glance at your method, but perhaps I've spotted it.

<dtml-in "decrQuery(_.None, _, datum=(_.str(datum)))" size=1 start=teller>

Why should this datum (in _.str(datum)) be known to zope?

I thought it was needed to feed back again the date information. Bad thinking and probably an example of mindlessly copying some code from another method. The warnings about the global name 'datum' are gone now when I press the submit button: i get a blank screen, which is much more user-friendly. Hope it has taught me something about needlessly throwing in unneeded variables, though. Thanks, cheers, Dirk