hmm that its strange your code did not worked.
But have managed to get it working other way.
Code:
$pathvar = 'rtmpdump.exe -r "'.$rtmp.'" -a "live" -p "http://castalba.tv/embed.php?cid='.$cid.'&wh='.$wh.'&ht='.$ht." --live -y "'.$playpath.'" - | "vlc.exe" - &';
echo $pathvar;
echo exec($pathvar);
Many thanks!!!