Why won't it PDF? What error is it showing? Do other presets work? What does your layout look like?
Have you tried removing elements one at a time and exporting it and seeing which element is causing the issue?
Have you got images on the page - perhaps resaving them to a different format and relinking them will help?
I sincerely doubt it's out of memory, seen as I work on a computer with 3gb RAM and a Intel Core 2 2.13ghz processor and I never get that issue.
Make a copy of your document. Delete half the itmes, then try to make a pdf. Keep repeating this process until you locate the exact object that is causing this. We can then better deteremine what the problem might be. Some common possibiliites:
- Image with a bad color profile
- Image with a duplicate cliping path directly on top
- Bad font (Multiple Master, or font cache needs clearing)
Also try using another pdf preset to see if that works, like PDF X.