iTunes 9 may not start after a clean install and display the error “Apple Application Support was not found”.
This module can be separately installed.
Download the latest iTunes version.
Use a file decompression programme (such as winzip or winrar) to extract the module from ‘iTunesSetup.exe’.
Copy the file ‘AppleApplicationSupport.msi’ on your local drive and run it. Once the installation is succesfully completed, iTunes should work.
Related articles on installation files can be found on the Apple Support Pages