<http://kb.adobe.com/selfservice/viewContent.do?externalId=kb402767&sliceId=2>
on that page you'll find this note:
Start out at Level 2 and advance to Level 3 only if you still have issues
installing your CS3 applications. Running this script removes shared components
created during the installation of CS3 applications.
Note: Level 3 is a hidden option and thus is not listed in the main interface.
To access Level 3 just type "3"( without quotes) when prompted for the
level.
glad to hear it martyn!