PHP: session seems to be lost after header redirect only on IE

[Blix]

I can't find a good answer for this anywhere.I have a login page, and after a good login it redirects to main page.In FF, and chrome - works perfect. On IE it doesn't work. I keep losing the session when I get to the main page.I have checked the following:- session_start at top- no blanks or anything befoer header redirect- one line before the redirect, IE knows the session user id, but after the redirect, just one line after the session start, it loses the session user id- I've checked it also on other computer - same resultsWhat is wrong with IE? or what could be wrong with my script ?Thanks