I think kidsolo's suggestion may or may not help to stop exploits. My guess is that it wont stop exploits as this probably only stops adobe reader from opening non .pdf extension files or files with a wrong mime header. I think the pdf exploits are deployed as pdfs.
Deliguy thanks for your help. Unfortunately, when internet explorer is presented with a pdf file, this doesnt stop it from opening the pdf inside the browser with adobe reader and thus executing the exploit.