replacing 2.3.1 video embeds with 2.4 video embeds

I've just upgraded http://youcantstopthisdancer.com to 2.4 All in One Video Plugin, and it's working great.

For a few weeks now, I haven't been able to get videos to play from the earlier plugin versions. (I'm running 2.9-rare wordpress)

New embeds from 2.4 are beautiful, and I'd like to replace all the old video players on the site with the new ones.

Has anyone tried this?

Here is an old post where the video won't play: http://youcantstopthisdancer.com/2009/09/one-year-two-weeks-ago-i-got-ch...

and here's a new post where the video works: http://youcantstopthisdancer.com/2010/03/279/

Any help migrating the posts or troubleshooting why the old videos aren't working would be great.

--Drew