Hard to help further without the full model number of the TV - have a look on the back when you get back and you should see it.
Also, just downloaded the Apple TV manual, page 15 says:
If you see just a black screen the first time you use Apple TV, make sure the input you've selected on your TV matches the input you've plugged the cables into on your TV or receiver. If the input matches, you might need to select a screen resolution your TV supports. See "Problem? No problem." on page 27 and refer to the documentation that came with your TV for information about its inputs.
Page 30 of the "Problem? No problem" section details this:
If your TV screen still appears fuzzy or black, you may need to select a video mode your TV supports. To select a video mode:
1 Press and hold both MENU and + on the Apple Remote for about 6 seconds.
2 Press + or - on the Apple Remote to cycle through the display resolutions.
3 When Apple TV reaches an acceptable display resolution and "If you can see the Apple logo, select OK" appears on your TV screen, press Play/Pause .