IE7 File association redirect

I frequently try to view bills, maps etc in .pdf from IE7. Each time I am presented with the “open, save,cancel” window. I can save or cancel, but if I want to open, I always get this window:
http://shell.windows.com/fileassoc/0409/xml/redir.asp?EXT=pdf
Acrobat 8.1 is clearly associated with PDFs. It is a pain to save, then open…and frequently delete files I just want to see.

Searching Microsoft.com is predictably frustrating and unsuccessful.
Any ideas?