streaming freezes although adaptive buffering

Hello,
I have done a flash banner with streaming content on my page...the problem is that although I am using advanced buffering to detect visitor´s bandwidth and according to that to preload corresponding number of frames in advance...it freezes for the first time it is played ...??? Has anybody got any clue why it happens please ???
Thanx in advance
You can see it on my site
www.meerahmax.cz
There is also the .fla source file

I am using flash mx 2004