I've had an identical problem with Acrobat Pro 9.0 on my MacBook. It's part of a downloaded CS4 Design Standard package and until recently the Adobe Update Manager kept the versions of PhotoShop, Illustrator, InDesign and Acrobat Pro 9.0 current. Problems arose when it went to update from v9.3.3 to 9.3.4. The download went smoothly but the installation stopped at about 80% and flashed the same message you attached.
As an alternative, I tried downloading the individual update, but that doesn't fully install either; it stops and an alert panel appears indicating that Safari and Acrobat must both be closed before it will continue. Both apps were closed, which I verified through Window>Acitivity, but the installation would not resume.
Calls to Adobe Tech Support are hopeless. So far 8 hours on the phone with Adobe's call center in Delhi have produced only the insistent refrain that I purchase the CS5 upgrade since a link to my purchase of CS4 is no longer available for love or money. Aside from the cost of an unnecessary upgrade, there's no guarantee that CS5 would not encounter the same problem. Good luck, I hope we both receive a helpful answer for this matter. Regards,
9.3.4_update _failed.tiff 104.5 K
As it turned out, I spent a couple of hours with Adobe a week or so ago and
got the issue resolved. As I suspected, there were some settings files that
were corrupted. Once the Adobe tech deleted them, therefore I don't know
what they were, I was able to manually download and install ALL updates to
Acrobat Pro 9.0. It is now current.
I also had a similar problem with Device Central for CS5 not updating. That
took a separate call to Adobe and another hour because the Acrobat people
cannot answer CS5 questions and vice versa. It turns out that my copy of
Device Central was corrupt and had to be reinstalled. Once that was
complete, all of my issues were resolved.
Perhaps if you call back to Adobe and ask them to delete the Acrobat
configuration files, then you will be able to install the upgrades.
Best of luck,