Here is a copy of what is between the [YOUTUBE] flags in your post in the other thread, obtained by clicking on the "QUOTE" button on your post there (Note, I've altered the brackets for the flags from square - [] - to squiggly -{} - so that it won't try embed the video here but just show the content of the post):
{YOUTUBE}<object width="480" height="385"><param name="movie" value="http://www.youtube.com/v/RLq7Aqd_H7g&hl=en&fs=1&rel=0"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/RLq7Aqd_H7g&hl=en&fs=1&rel=0" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="480" height="385"></embed></object>{/YOUTUBE}
Here is what Harry suggested you use:
{YOUTUBE}RLq7Aqd_H7g{/YOUTUBE}
based on the link you provided:
http://www.youtube.com/watch?v=RLq7Aqd_H7g
(note the bit after the "=" sign)
If you do what Harry suggests, I can see no reason why it wouldn't work, since it seems to work for moderators (eg. Harry and Nate), and the great, unwashed masses (eg. me) (not that this should make any difference anyway). Can you do the above (Harry's suggestion) in your original post, leave it like that, let us know, and let me/us have a look at it again?
Cheers,
Marc