I could get to work the form part of templating system by carefully reloading the files in the "right" order:
After the server start accessing the glossary add-page fails. But when i reload 0-procs.tcl and in a second step form-procs and element-procs everything is ok. (till the next reload of 0-procs.tcl that produces the same error as after startup)
The log file tells me that 0-procs.tcl IS sourced first in the startup procedure.
This is quite bad ! I am rather puzzled :)