I've never had that problem with mine,
I guess the standard procedure would be to double check your connections,
I would assume you ran the setup programs for the tv and sound,
Then the whole driver routine... uninstall and reinstall.
(I am pretty sure there is a direct-x specific driver for ATI_AIW video capture but now I can't seem to find it)
(sorry I've got nothing here)
I sometimes get some good info from Rage3d although they are prone to castigating newbies like myself for not being as smart as them.
Rage3d-Forum
I'll look around some more.