With 4.6 Player movie don't start

I download the 4.6 version of JW Player but I have problems to start playing video.

Before, I use the 4.2.9 version.
My movies are on progressive download server and are H264 encoded with .mov extension.
I had the param start to begin the display on 0.

With the 4.6 version, if I user the same parameters, the movies start before few minutes.
So I try to add ?start=0 after filename and the movie begin playing like before.
But with this parmeters, I can't seek into the movie. When I try to play at the middle, the player bufferise but no play movie.

Cant you help me please ?

function fctOpPlayer(arg) {
ttURL= arg;
var so = new SWFObject('player-licensed.swf', 'mplflashbanner20090917020924', '610', '380', '9.0.0');
so.addParam('allowscriptaccess', 'always');
so.addParam('allowfullscreen','true');
so.addVariable('autostart','true');
so.addVariable('backcolor','F2F2F2');
so.addVariable('bufferlength','10');
so.addVariable('displayheight','380');
so.addVariable('displaywidth','610');
so.addVariable('file',ttURL);
so.addVariable('frontcolor','757575');
so.addVariable('height','380');
so.addVariable('lightcolor','557722');
so.addParam('menu','false');
so.addVariable('screencolor ','000000');
so.addVariable('start','0');
so.addVariable('http.startparam','0');
so.addVariable('streamscript','lighttpd');
so.addVariable('stretching','uniform');
so.addVariable('type','video');
so.addVariable('width','610');
so.write('flashbanner20090917020924');
}