I went to your example, and uploaded welcome56k.swf.  Part of the problem reappears - after viewing HTML, the swf no longer plays.  I left it in your upload folder for you to try.  It is not erasing code, however, as I experience here.

 

I downloaded yesterday, but only replaced the contents of the bin folder.  I will replace the rest and see if that makes any difference.

 

(LATER...)

 

I re-downloaded today (4-23) and now I get the same result as on your site example - the code is no longer modified or erased when switching between modes, but after going to HTML view, I can no longer see the flash video play.  Only a white box is visible (well, invisible against white background - if you right-click on it, is says something about Adobe Flash, so it knows the flash is there, it just does not show up and play).