INOi Media Harddrive Error - Help!

I have just bought an Inoi 320Gb Media Hard-drive and after copying a few different avi/divx files have noticed that any files which are either 624 or 640 in width play on my TV with a black line down the right-hand side of the screen making the image off-centre. Some are even slightly too low down on the screen too losing the bottom of the image.

Files at a smaller size play fine (608 down-wards), and the one larger width file I have also plays fine. It’s just the ones at 624 & 640 wide.

I have tried different scart cables, a composite lead and even a different TV all with the same results. The files all play perfectly on my PC and when burnt to DVD play fine too. My TV is a standard 4:3, but am sure that it is not the cause of this particular problem.

Why this is happening? Is this an error with the hardware or something which can be fixed?

Thanks,
Sarah

Here is a link to the media player I bought:
http://www.maplin.co.uk/Module.aspx?ModuleNo=221340&TabID=1&source=1&doy=14m11