if you are using the windows version it is not your fault, my apologies, windows does not do openGL well with Panda3d, There is a SDK with directX thats runs with a full framerate, however there is no runtime builds that I can build a directX executable from, I guess licensing issues.
Edit: you may have experienced more then just speed issues with the windows version, I play it myself and it was not functional and the graphics didn't work, however, today, I updated the windows version to function, but the speed issue is still there.