I had the same problem and struggled with it also.
I finally solved my problem by uninstalling reader 9.1, air, acrobat.com and THEN after a restart, installing a lite version of reader 9.1 from this site:
I was getting the same error message. I am using Windows EX Home Edition. No virus protection is active at this time.
This error recently started with my version of Acrobat 9.2.
After the song and dance of repair, uninistall, re-install I made a final uninstall of version 9.2.
Upon looking over the Adobe site and their forums there appears to be many folks out there using different operating systems, configurations and software. Adobe / Acrobat seems to be ignoring offering a solution for everyone that is having this age old problem. So I ended up reloading Acrobat version 7.0. This works, so far.
Now, back to making music which is were I started with this 'any ole ways'.
Trying to Disable Protected mode per instructions at the bottom of this page: http://kb2.adobe.com/cps/860/cpsid_86063.html
Disable Protected Mode by going to Edit > Preferences > General and deselecting Enable Protected Mode at startup.
But when get to that location, there is now check box option for "Enable Protected Mode at startup"...please help!