Memory problem complaint

I coded a matlab file with a few big matrices in that as variables. The file size appers to be 70Mb. I exited matlab. When I go to reopen the file, it complains that there is not enough memory to open the myfile.m. When I click on the help radio button of the error message it says that I have to change something in the Java.opts file. Can somebody please help?I am running Windows xp with a Gig of ram.