Internet explorer timing out with Windchill

Hi:

I am having a problem with Windchill timing out in Internet explorer. After about 1/2 to 1 hour interenet explorer gives me the page cannot be displayed when I try to use it if it's been sitting idle for that long. This happens in an external browser and the embeded browser. I also lose connection to the Windchill server and get a CIP SOAP CLIENT; Failed to open first connection.

If I close everything down and wait a few minutes everything seems to be fine. Any ideas?

Note this is Windows 7 with Internet explorer 8 with Windchill 8 and 10. This does not happen if I am connecting to the Windchill 10 server as far as I can tell.