Firefox is foxing me around? Need a hand

Hi Chaps,
This has been turfing me off for a couple of days. My app works fine in IE7. When I clear my cache in firefox and start from the beggining it doesn’t work properly. After roughly 5 reloads of passing the information through the browser (not clearing cache) it starts to work in firefox.
Yes it eventually starts to work after 5 tries. But I need it to work 1st/uncached time obviously. Can anyone enlighten me?