Corrupted files relate to Quest Installer.
Try reinstalling the Toad for Oracle 10.6 trial using the trial installer. This should be able to run. After the Toad trial has been reinstalled, go to Start | All Programs | Quest Software | Quest Installer | Quest Installer and choose to uninstall Toad and other applications from there.
Do not uninstall from Add/Remove if the application is suppose to be in QI. You do not need to uninstall QI to install Toad again. Once other Toad apps have been uninstalled you should be able to run the commercial install again, to reinstallt he commercial version.
The install.log file was missing.
