Ati radeon hd 2400 pro hdmi problems

I have a ATI Radeon HD 2400 Pro made by VisionTek. There are three ports in the back VGA, DVI, and HDMI. When I hook the TV up to the video card via the VGA port it detects it fine and can output to the TV perfectly, but for some reason when I hook it up using the HDMI cable, it won't detect the TV =(. Does anybody know what might be happening? Thanks in advance.

EDIT: Also, I just registered here and I couldn't validate my account using my e-mail. It says, "Message: Error." so if a mod sees this could you perhaps send another validation to ryanabella@gmail.com? Thanks =).