I've downloaded the latest JW player, 4.4.192 licensed version... and the player is being embedded fine through embedSWFObject, but the playerReady function isn't being called.
This is what its embedding, so I don't think its a script access problem:
<object id="player1" width="720" height="405" type="application/x-shockwave-flash" name="player1" data="/includes/javascript/video/player.swf">
<param name="allowfullscreen" value="true"/>
<param name="allowscriptaccess" value="always"/>
<param name="flashvars" value="autostart=false&controlbar=over&skin=/includes/javascript/video/dangdang.swf/>
</object>

Are you testing this on a Linux client?
v4.4.192 works well for me, embedded with swfobject v2.2. No problems calling the playerReady() function.