I was having trouble with a blank page appearing everytime I tried to view a PDF file in Firefox, but everything working fine in Konqueror.

After searching through the plugins I realized that there were two plugins attempting to handle PDF files. I renamed the Acrobat PDF plugin as

sudo mv /usr/lib/browser-plugins/nppdf.so /usr/lib/browser-plugins/nppdf.so.bak

and PDF files now work in the browser for Firefox and Konqueror.