Will have a wild guess and say while vid is loading you get a blue "Q" in the window ???
If thats the case go to quicktime player run it
at the top hover or click over edit till menu appears
on that scroll down to preferences which should then show an option for
"quick time preferences" click that then on the tab at the top click
"File types" look down to "miscellaneous file formats" and make sure
"SMIL 1" and "FLASH MEDIA" are UNticked and
"QUICKTIME HTML (QHTM) IS ticked

All that is as lomg as you got quicktime ver 7.1.3 or newer as the version just before could NOT be made to work, so even if all above dont work would be worth downloading the latest quicktime.

and then a flash player and macromedia player but recon you probs already got them or it will tell you you need em ONCE you sorted Quicktime out

And if that works think your self lucky cos took me months to get mine working


Steve