desga, it seems to be like yahoo inbox preview for pics
i don't have the problem on my default kmeleon but on the test version(default profile prefs) it had the same problem like matias and tubbie which was quite strange and meant not isp or connection.. i checked googlecode youtube bugs and many were complaining about the same issue but without a single response from a developer.. when that happens=something fishy
youtube/google is punishing you for blocking ad cookies(third party), i enabled all cookies and the problem was gone instantly
matias and tubbie, open preferences>privacy and select always for accept cookies
fred, i added your macro to youtube services extension but made it into kiok mode(no toolbars)
http://kmext.sourceforge.net/macros/youtube-services_v1.3.7z
fredtube{
menugrayed=(substr($URLBAR,0,31)!="[http://www.youtube.com/watch?v=");
$kioskcomm=("-webapp");
$k_path=getfolder(RootFolder);
$_video_addres="";
$_video_addres=gsub("watch?","",$URL);
$_video_addres=gsub("=","/",$_video_addres);
exec($k_path."\\k-meleon.exe " .$kioskcomm. "". $_video_addres);
}