I was able to solve it. When I got the new distribution of Python with Poser (2.0) The Poser installer did not remove the preferences from Python 1.5.3, which I had previously installed. I deleted them and now it works fine. You should also avoid to run several distributions of Python or TCL/TK parallel on one machine. The same holds for TCL/TK. TCL/TK (V 8.3) installs a folder in your "System Extensions" folder called "Tool command Language". In this folder are 5 aliases. In order for TK to run, theses 5 aliases should point to the respective files in your Poser: Runtime:Python folder. If you install TK seperately these aliases point to somewhere in the desert. You can also run into problems if you move your Poser folder on another harddisk or into another directory, then the aliases are not correct anymore. Learned again something: Be careful snakes may bite Karl