'Illegal characters in path' error when trying to install Toad (4243056)

Unresolved variable value in one of desktop's Environment Variables:

e.g. "%Java_Home%" (although it may be another variable that has incorrect information)

Amend the environment variable so it is correct, and the error should not occur the next time you run the installer.

To edit environment variables:

1. Search for 'Advanced System Settings' on the desktop
2. Click 'Environment Variables'
3. Review both the System and User Variables for a path location value that may no longer exist or is incorrect. Once found correct, or remove. | OK 
4. Retry installation

If the error continues, or you are unable to identify which variable has the issue, then try downloading the MSI (Special Installation only), extracting the MSI files and manually installing the products relevant to the Toad edition.