Thanks Bhavbhuti,
I create a thread here in Chatter Section with this question & here what Michel said:

"Your browser is not reading from the server. You will need to force that manually. The next time you'll have that page, simply right click refresh to get the files. This will do"




>Hi Borislav
>
>>Once I posted a message to Michel about Opera & he said me that with IE all works :o)))
>
>This time it won't be avoidable, as FireFox is gaining acceptance pretty fast.
>
>I'll try http://forums.mozillazine.org/ for this question and let you know if there are any solutions.