Repeated message "Before proceeding you must first launch Adobe Acrobat and accept the End User

I am now getting repeated pop-ups of a dialog box that says:

Before proceeding you must first launch Adobe Acrobat and accept the End User License Agreement.

However, there is no menu command or preference to do so in either Adobe Acrobat Reader X version 10.1.6, or Acrobat Pro X 10.1.6 CS6 (I'm a CS6 subscriber)

How can I make this annoying dialog go away? What caused it to start appearing?

I'm running OSX 10.8.2 on a recent iMac, Safari 6.0.2 (8536.26.17)