Can't Get pdfs to Open with Acrobat in Safari

I cannot get Safari to open or download any pdfs in Acrobat.

If I go to a page that has a pdf, it opens in Preview.

If I go to a page (like my online banking sites) that downloads statements, it does nothing.  I just get a non-printable screen.

It works on other computers not running Safari 5.1.2 and Mac OS 10.6.8.

A clue: for whatever reason, neither the Adobe Reader nor Adobe Acrobat (I have both) plugin appears in user/library/internet plugins.  In fact there is nothing in that folder.  I do have the Acrobat preferences set to display pdfs in browser.

Any help out there?