djdb,
The problem you’ve described sounds a lot like the problem I was experiencing, although I had it in offline play. Be sure to check out the thread, “Mid-game hang-up”.
http://www.planetmule.com/forum?topic=1829.0The main problem for me was the OpenGL settings for my graphics. Once I was able to set it for triple buffering it pretty much eliminated the problem, although I haven’t tested it with online play yet. You may want to adjust your graphics for performance rather than quality. What are your video specs?