Same problem
Example:
http://service.t-online.de/t-on/kund/prei/star/CP/cc-preise-agb-start.html
Go to this site an try to open/download a pdf file. I got a white site. Acrobat Reader is installed. K-Meleon don't open the site with Acrobat Reader or trys to download the file, just got a white site.