One thing that causes this is if your application crashed previously and you started it again and loaded a MapPoint instance again. If this should be the case, try eliminating any instance of MP stuck in the task manager before running your app again. If this is not the case, then another common cause is if you are shifting focus in your application to other controls or if you switch windows when the extended processing is being carried out. Try to keep focus on the app window during the processing to avoid this. I use a progress bar to give some feedback and to avoid this server busy dialog when doing some heavy processing with MP. Hope this helps you.