Ah, Mike, a common mistake...
You used the URL that leads to the YouTube page within which the flash player is embedded... but to host it here you need to include the path to the actual flash file instead.
You used this:
http://www.youtube.com/watch?v=F1dAedHmsukBut you should have used this:
http://www.youtube.com/v/F1dAedHmsuk&hl=enThe key difference is in the ?v= command in the first string of code, compared to /v/ in the second string of code. The actual URL in the first string is just
http://www.youtube.com/watch (which directs the browser to a directory one level down from the main youtube directory). The ?v= is actually a bit of information that tells a script on that index page where it can find the proper video (namely in the /v/ sub-directory which lies still deeper in within the main youtube domain) and what the name of that video is (which is F1dAedHmsuk).
As for the video itself, it resides at
http://www.youtube.com/v/F1dAedHmsuk and the extra &hl=en is just more data for a script on that page, to let it know the language is English.
Try going directly to
http://www.youtube.com/v/F1dAedHmsuk sometime and see what a youtube video looks like without the page it's normally framed in... It will be bigger and scaled to fit your browser window. That's the part you need to list in your code here, to host it here (the notation about the language being English is pretty much optional).
So, here's the correct format:
[flash=425,355]http://www.youtube.com/v/F1dAedHmsuk[/flash]And here's the end result:
http://www.youtube.com/v/F1dAedHmsuk