I have to create a fairly large double array 12000ish x 55000ish. Unfortunately, I get an out of memory exception. I used to develop in Java and could change the memory sett
Well either you are out of memory (close some programs) or you're hitting the memory allocation limit (about 2Gb), this memory needs to be a contiguous block. You could use a 64bit machine in which case you'll have more memory available or I think you can make the application large address aware (googling will tell you how to do this if it's possible in this case).
Believe you add a /3GB switch to the Boot.ini file for the large address awareness.