After trying to diagnose an issue with a SWF suddenly not working in IE, I found a nice piece of code on (of all places!) Google Code. The swfObject code is a standards based method of embedding Flash files into an HTML document. The page comes with a builder app that creates the code needed to properly embed a SWF ... and it works ... using the techniques in the file, my IE errors suddenly vanished.

Get it at: http://code.google.com/p/swfobject/