Ever had an issue installing a program on Windows, Mac or Linux? Installing applications might sometime fail because of some seemingly unknown error. If you are experiencing installation failures this is most likely due to permission errors.
To resolve your error, run the application that you are trying to install as Administrator and install the app one more time. The administrator is an account on your computer that, when you have access to, can do anything he/she likes. This 'do anything' means anything from deleting important system files to enable you to install new software on your computer.
If installing your application as Admin fails, try to install the application from another folder were the .exe or .app is located as the installation file might be used by some other process in the operating system. If all else fails, start with the basics. Reboot your computer and try to install the application again.
If that fails, try to install the application in safe-mode. All major OS'es has some form of safe-mode which acts as mode that disables features that 'are nice to have' and just enables core functionality of the OS so you can troubleshoot easier.
Hope this helps.