3D View Port support required

Hello I have a problem with my 3D View port The screen is not full about half of it is cut off. I have an image here to help show what I am talking about for I don’t know how to put it into words. Any help with resolving this problem will be greatly appreciated.

Edit: The part with the big white “+” is where the problem is accuring along with the black top border with the green and blue in it. Version 2.48A on ubuntu

http://lh6.ggpht.com/_Qf1cDbKapRE/SlijaONxLzI/AAAAAAAAAB4/fjw0973Ma8M/s640/Screenshot.jpg

What is your graphic card?

I had the same problem on an intel GMA X3100.

My problem was the broken state (or rather intermediary) of intel drivers in ubuntu 9.04.
I resolved it by buying an radeon HD card. Right now blender work flawlessly.

If buying a new card isn’t an option, you can always revert back to ubuntu 8.10, wich work flawlessly and wait for the drivers to stabilize in (hopefully) ubuntu 9.10.