There is not a documented pref for disabling that prompt, but it is possible one exists.
If you want to do some detective work:
- Start with an install that will prompt you but don't open Acrobat.
- Take a snapshot of the registry (regcompare works).
- Open Acrobat and perform actions that show the prompt.
- Click Yes.
- Close Acrobat.
- Take another snapshot.
- Compare snapshots.
You'll see a long list of stuff that's changed, but if there is a related pref, it may be obvious.
HTH,
Ben