In order to run OnTheClock Desktop import Tool, you will need to have .NET 3.5 Framework installed for the program to run. 

You may encounter an error such as

1.) You can reboot the system and try to install the framework again 

Another option would be to follow the steps in this article: https://docs.microsoft.com/en-us/answers/questions/112308/error-code-0x800f0954-on-windows-10.html