iPod touch not responding to touch!

I've just bought an iPod touch today. Right out the box, after syncing it with iTunes, I was only too eager to start playing with it... Only to my dismay, part of the "touch sensitive screen" is not responding to touches. The area of my iPod touch affected is the center portion of the screen... due to this, I can't adjust brightness and many other options, which I can't use or navigate properly.

I've read around the apple discussions, and I noticed that some other users have the same problem. For them, different parts of their screen is not responding to touches. This is a really stupid problem to have. But it is a problem, nevertheless. I bought a brand new iPod touch, and it's already a defect. Obviously, I'm very unhappy with this.

This might be something affecting a small majority of the iPod touches out there. But it also might be a problem waiting to affect other owners.

Does anyone know whether this is a software or hardware issue? Should i just bring the iPod touch to the authorized dealer and demand an exchange (which might have the same problems)?

Any information from you guys would be greatly appreciated. Thanks in advance.