The only solution for it is to
1) Uninstall Acrobat
2) Re-install the acrobat using new user account
3) Then update it.
however this are link for your help:-
After you remove acrobat, Try booting your mahcine in Safe Boot mode first and then enable the root user and try to install Acrobat 9 followed by its updates.
Start in Safe Boot mode | Mac OS X : http://helpx.adobe.com/x-productkb/global/start-safe-boot-mode-mac.htm l
Enable Root user : http://support.apple.com/kb/ht1528
Hope that Helps.