Firefox become hang after upload image from computer ?

I am facing a weird kind of problems with my firefox 5. It become hang whenever I upload an image from my computer to my facebook account or when i attach file in my mail account. So, plz tell wat kind of problem of this wat should i do remove this problem........????

I never face this problem with my firefox so i can't help you in this b't the guy who face this problem may help in this ... !