QGIS not Printing to PDF

Simple QGIS 1.8.0 not printing to PDF. Suddenly stopped. Is this an error or something. the resultant PDFs are blank pages.

When i file print and use a pdf printer it creates blank docs. when i export to pdf it crashes. when i export to jpeg it does not print map.

Answer

I think it was the same old issue of lack of memory. In the end i reduced to 200dpi exported as jpeg and coverted to pdf after the fact. All in all i have it wrote down to too much information and too small of processor for this task...as it was massive.