Hi Jorge and thanks for your reply
the troubles are that 8 times on 10 the upload doesn't complete
when the upload is complete, the listener onComplete is not called
you want the code ? basically this is the upload code found on this forum....
it has been working fine for months, and i didn't made any changes in the upload code. I've been testing with IE8, FF3, OPERA9, each time same result...and each time i'm starting upload, browser will take 50% cpu, but i don't have error message saying that "a script may slow the animation etc...'