I've had this exact problem. I'm assuming that you've got a function which periodically makes a request to the server to fetch data then updates the page if that data has changed since the last time you made the request.
Internet Explorer will cache the results of Ajax calls to the same resource even if you tell it not to in your HTTP headers. So if you make a request to get_data?id=whatever
over and over again, IE will make the request once and then stop making it in the future and simply return the result of the first request.
The solution is to add a dummy parameter to the request string. So first you request get_data?id=whatever&ie_hack=0
then get_data?id=whatever&ie_hack=1
etc. This will stop IE from caching the results and force it to make the request each time, since it sees a different query string for each request.