prueba con esto dentro de tu html , a mi me funciona en firefox.
<object classid="clsid:D27CDB6E-AE6D-11cf-96B8-444553540000" codebase="http://download.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=7,0,19,0" width="924" height="540">
<param name="movie" value="../seg/swf/inicio.swf" />
<param name="quality" value="high" />
<param name="wmode" value="transparent" />
<embed src="../seg/swf/inicio.swf" width="924" height="540" quality="high" pluginspage="http://www.macromedia.com/go/getflashplayer" type="application/x-shockwave-flash" wmode="transparent"></embed>
</object>