Thanks for the quick reply. I put in a div tag as suggested, though nothing changed. It still blanks the source

<div><object width="425" height="355">
<param value="about:blank" name="movie" />
<param value="transparent" name="wmode" /><embed width="425" height="355" wmode="transparent" type="application/x-shockwave-flash" src="about:blank"></embed></object></div>

I  also tested it on my local install version 4.05.03, and it has the same behaviour. So still no joy ...

Can I ask someone to confirm this bug in the latest version of DNN as well. I am wondering if FCKEditor in the latest version is any different.

This happens anywhere FCKEditor is shown. Currently I have seen it in Text/HTML and News Articles Module.  Interestingly, if I switch to text only in a TEXT/HTML editor, I can insert the flash embed code and it gets saved and displayed correclty. However, when you go back to edit it, it switches back to FCKEditor by default and that clears the source component of the flash embed. So the problem is definitly around fckeditor and its interaction with DNN.  As you suspected must be around security (I think). But where to check it is something I dont know.

I had a look at fckconfig.js and the only flash related stuff I can see are these, which are not inspiring.

FCKConfig.FlashDlgHideAdvanced    = false ;

FCKConfig.FlashBrowser = true ;
FCKConfig.FlashBrowserURL = FCKConfig.BasePath + 'filemanager/browser/default/browser.html?Type=Flash&Connector=connectors/asp/connector.asp' ;
FCKConfig.FlashBrowserWindowWidth  = FCKConfig.ScreenWidth * 0.7 ;    //70% ;
FCKConfig.FlashBrowserWindowHeight = FCKConfig.ScreenHeight * 0.7 ;    //70% ;

FCKConfig.FlashUpload = false ;
FCKConfig.FlashUploadURL = FCKConfig.BasePath + 'filemanager/upload/asp/upload.asp?Type=Flash' ;
FCKConfig.FlashUploadAllowedExtensions    = ".(swf|fla)$" ;        // empty for all
FCKConfig.FlashUploadDeniedExtensions    = "" ;