IE 5.5 sp2 script debugger messages

When attempting to access internet via T1 connection the page begins to load then locks up the Workstation. When we end the task we get Cannot close while debbuger is running. That will repeat itself each time you attempt to end the task and cascadethe message down the screen. A power off is required to get machine back up again. We upgraded to 5.5 SP2, symptoms are the same. It appears that this gets more frequent as the day goes on. I checked NIC and it appears okay.