Error 1638 and Error 1603 When Installing Webroot SpySweeper

The other day I encountered an Error 1638 while installing Webroot SpySweeper version 6.0.2.39. The installer proceeded to the point where it asks if you would like to install the Ask! Toolbar, then clicking Next, the installation begins and produces Error 1638. After the following steps were taken, the error no longer appeared, and the installation completed successfully.

Go to this Microsoft Support web page and download the Windows Install Cleanup utility. Install and run the utility. If the installation is attempted again at this point, error 1603 is produced.

Delete any Webroot folder in the Program Files directory. Go to the following Webroot support page and download the appropriate SafeCore.exe file. Save it in the same folder as your Webroot installation program. Note: The SafeCore.exe available for version 6.0.2.22 of SpySweeper worked for me in this case.

Reboot the system, then try the Webroot SpySweeper installation again, and it should work.