I haven't seen this issue, but I can undestand it being annoying and disconcerting. I have been using MagicInfo pro for ages and not experienced this problem. I would only suggest that you ensure having the correcty versions of the software, I use 3003 for client and 2508 fior server.
Also, some data switches may have issues so although the LAN maybe ok, the switches do strange things sometimes. What make are they and are they managed switches?
Bill