So I spent half a day trying to figure out why a Flash project suddenly stopped working properly in IE. Out of the blue, the SWF file would not honor the color designated in the bgcolor parameter. Worse, it stopped allowing the Flash application to change to full screen even though I sat allowFullScreen to true.

In the end, it was human error (yeah, mine). I had added another parameter (allowScriptAccess). The problem was that I set its value to "true". Well the only three valid values are "sameDomain", "always" and "never". Put the wrong value in there... and suddenly some of your other parameters may no longer work (in IE at least).

So if you read this, I hope it saves you a little time. Check your parameters and make sure their values are valid.