ok, after many attempts I discovered that my own slideshow module also creates this error, I'll need to deal with that
further more, I used a different method, described here:
http://www.adobe.com/devnet/activecontent/articles/devletter.html#multipleoccurrencesthe code below worked for me
<script type="text/javascript">
AC_FL_RunContent('codebase','http://download.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=7,0,19,0','width','135','height','500','wmode','transparent','align','middle','src','<?php echo $mosConfig_live_site; ?>/templates/<?php echo $cur_template; ?>/Sponsors','quality','high','bgcolor','#ffffff','name','Sponsors','allowscriptaccess','sameDomain','pluginspage','http://www.macromedia.com/go/getflashplayer','movie','<?php echo $mosConfig_live_site; ?>/templates/<?php echo $cur_template; ?>/Sponsors' );
</script>
<noscript>
<object classid='clsid:d27cdb6e-ae6d-11cf-96b8-444553540000' codebase='http://fpdownload.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=5,0,0,0' width='135' height='500' id='Sponsors14' align='middle'><param name='allowScriptAccess' value='sameDomain' />
<param name='movie' value='<?php echo $mosConfig_live_site; ?>/templates/<?php echo $cur_template; ?>/Sponsors.swf' /><param name='quality' value='high' /><param name='wmode' value='transparant' /><embed src='<?php echo $mosConfig_live_site; ?>/templates/<?php echo $cur_template; ?>/Sponsors.swf' width='135' height='500' wmode='transparant' name='Sponsors' align='middle' allowScriptAccess='sameDomain' type='application/x-shockwave-flash' pluginspage='http://www.macromedia.com/go/getflashplayer' />
</embed></object>
</noscript>