web interface not playing media

hey guys I just recently got adsl and was busy setting up the web interface. I have set It up on freinds computers before with no problem.
when I set It up on my network I can brows threw all my media but I am not able to play anything...

I checked my settings everything seems to be fine.
I tried installing a different web interface but I have the same problem...
anyone have a solution to my problem?