There's a possiblity that for whatever reason your screen is set to a mode your TV won't work with.
An example of this is an NTSC TV with the videomode set to PAL. It could have been something you accidentally set or something. I did it oncewith the XDK using a button combonation or something. Still have no idea how exactly I set it, but my screen went crazy and I couldn't fix it withoout the Enigma Video Mode Switcher