I'm on OSX 10.5.6 with FF 3.06 and have no problems.

You may want to get the most recent plug in from Adobe [get.adobe.com].

this was the only way i could get it xhtml validated on my site:

<div id="flash-header">
<object
classid="clsid:D27CDB6E-AE6D-11cf-96B8-444553540000"
codebase="http://download.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=6,0,79,0"
id="bluecruiseidaho"
width="800" height="175">

<param name="movie" value="bluecruiseidaho.swf" />
<param name="bgcolor" value="#FFFFFF" />
<param name="quality" value="high" />
<param name="allowscriptaccess" value="samedomain" />

</object>
</div><!-- end flash header -->