[Plugin: Viper’s Video Quicktags] WordPress MU 2.9.1, pulling the embed?

In the midst of developing a new site and upgraded MU to 2.9.1 Then tried to install Quicktags. I’m using it on other sites and it’s working beautifully, on this site however MU is just not allowing it to work. I put in [youtube]https://www.youtube.com/watch?v=VKTEzULzCrc[/youtube] and it gets parsed, but it’s just completely stripped with nothing put in it’s place. Is there something I’m missing (likely some setting in MU that I’ve forgotten to update?)