Cant play videos

Ican upload videos..But i am not able to play the vieos..How can i rectify this problem?

This may be video not convert to flv .can You post the site url.

I do have the same problem.
can you guys help me out here?
When i upload the video the page became blank.
I have been trying for ever and i also contact my hosting company and they sais it's my upload.tpl file that is not working properly.
Any help will be very much appreciated.
Thanks