Error 1721.There is a problem with this Windows Installer package. A program required for this install to complete could not be run. Contact your support personnel or package vendor

I had trouble uninstalling a program from Windows 8.1 and the above message showed. For a change I did not end up having to use any Third-Party tools to solve this problem. Microsoft has a useful tool which will help resolve Install and Uninstall issues related to Microsoft Installer

Using below link will guide you through

http://support.microsoft.com/kb/290301

Strangely, Microsoft does not link the Error 1721 to this post. If it did, I wouldn’t have to write this post

Happy troubleshooting 🙂