Hi,
Are you trying to play the HTMl5 or the SWF content ?
If it is the HTMl5 content, playing on IE8 might have problems. IE8 do not have a strong support for HTML5 content. Please try with IE10 or above.
SWF content should play fine on IE 8 with latest flash player.
Thanks
Alpi Agarwal
Adobe Presenter Engineering Team