error code 1607 - install shield scripting runtime error

I have just removed itunes from my pc and when I want to reinstall it again with the software CD in the drive and license code available, it gives me some error code 1607, install shield scripting runtime error? Can anyone tell me how to solve this issue? Thanks.

You will have to reinstall the InstallScript engine, follow these steps:

1. Download the IsScript7.zip file. To do this, visit the following InstallShield Web site:
   http://support.installshield.com/kb/.../IsScript7.zip
2. Extract the IsScript7.zip file.
3. Double-click the isscript.msi file.