Photoshop Error;Scratch disc Full

Ok im a total newbie to photoshop. Cs3
i just downloaded it and when i click new for a new project and for;

width i put ; 550
and height; 130

and i set it to pixel/inch cuz the only other option is pixel/cm

and when i press ok teh first error it gives me is

"Documents Greater then 30,000 pixels in either dimensions may not be compatible with older versions of photoshop and/or other applications"
if i press ok on that then it gives me another error saying
"Cannot complete the command because the scratch disks are full"

anyone know why this is and how can i fix it?

Oh and i downloaded the 30 day trial. if that has anythign to do with it. cuz evertime i open the default size it opens fine.

It sounds as though you have the unit values for height and width set to inches. If this is the case, then a document that is 550 inches by 130 inches @ 72 Pixels/inch, will produce a file that has more than 30,000 pixels on the long side. 39,600 to be precise.

That will make a document that is over 1Gig in size.

The second part of your question is related to the size of the image file. Photoshop uses a part of your hard drive when there is not enough physical memory. This is the scratch disc. The error is simply tell you that there is not a single contiguous piece of drive that is big enough to be used for an image of this size. The size of the scratch disk needed is much larger than any individual image, as it must allow for all of the processing of an image during the various operations you might want to carry out.

Correcting this is as simple as making sure the height and width is also set to pixels if you are going to enter the image sizes as pixels. Otherwise, enter the values as the true size of the image in inches.