I haven't tried the Flow Player myself, but it's possible there could be some conflicts with Javascript variable names - that's the only scenario I can think of that would cause them to create a conflict. If you have more detail on the actual Javascript error, that would help to pinpoint the portion of code.

JB

view.php was modified after installing Youtube BG
it was fixed after reloading the original view.php

Ok, great to hear. If you're happy with the support provided, I'd really appreciate a positive review in the C5 marketplace:
http://www.concrete5.org/marketplace/addons/youtube-background-omg-...

You can also check out our other C5 add-ons at:http://c5extras.com/

JB