PDF file upload error

Hi,

We are facing a strange problem. Whenever our users trying to upload PDF files, we get a message 'Low system memory.Cannot process the application' and the systems hangs. but this is not happening for other file formats like MS Word.We tried to increase the RAM size to 1.5 GB, but the problem is still there.Is it because the PDF files are very large in size?

How can we overcome this.