Martin Sell (thanks!) reported that threading via scripts was not working in the game engine with Blender 2.46 and later. My fault, to make pynodes work properly with threads > 1 I disabled Python's "check interval", preventing threads created via scripts from receiving time to run. Now only during rendering check interval is disabled (set to max int). Still experimental, I added the calls in BPY_do_all_scripts, since it's called in BIF_do_render, but will probably move the code to its own function after more testing & feedback.