Mythbuntu won't play videos in frontend

[Pascal11110]

I've searched the internet for hours at this point and tried quite a few things, so it's probably something stupid I'm missing. I did a fresh install of the newest mythbuntu (11.04 32 bit) and everything works great except I cannot get videos to play in the frontend (I've tried .mp4 and .mkv), but videos work fine in vlc outside of the frontend. Any suggestions?

[Pascal11110]

And just fyi my player settings are set to use Internal currently but I am open to using mplayer if that would fix it. Also my hardware specs are:

4 Gigs 5300 ram
Pentium D 3.2 Ghz processor
8800 GTS 640 MB video card
Gigabyte motherboard