setInterval not working in I.E

I have a flash 9 app that calls a php script that in turn pulls in some variables from txt files. The function within the flash file that calls the php script operates via a setInterval() function. For some reason, this works fine in Firefox and Safari, but in IE the swf fails to update the fugures unless i clear the cache and reload the page…rather than the setInterval() function doing so every 60sec…

Can someone please advise me as to possible problems/workarounds?..

Thankyou in advance