duckmango, I haven't got something larger in mind really. I just thought a Python shell in Poser would be a nice idea to try things out interactively. So I tried to embed IPython, which wasn't very successful. So I started to program my own shell with a simple Tkinter GUI. Along the way I added a function to call the Python Windows help and struggled with the diverse spawn*, exec* functions in the os module. Since all experiments haven't worked out properly, I started to use a separate thread to start the chm file. This finally worked ok when starting outside of Poser, but then: no thread module in Poser! So this is how I discovered the missing thread module. stewer, how did you disable threads for P5? There isn't any thread module in Poser5's version of Python. Apart from that, dis/enabling threads would mean recompiling Python itself. Could you tell me more, I'm really curious. Another thing is that before I exchanged python22.dll, I had to start my script 2 times before I got the Tkinter GUI and Python was reacting queer sometimes i.e. sometimes it just ignored commands. After the exchange everything worked fine.