Tired of pdf check message: How to kill it?

Every time I download and open a pdf, I get an annoying error window asking me if it's ok to open the file. I finally realized it had the Norton symbol in the lower left, so I went to the product to turn off the check. In Settings:Firewall:Intrusion settings I see something for Download Intelligence. However, when I turn that off, I still get the pdf file open check.

Where is the setting that turns it off?