Access denied when copying file to GAC

I was trying to copy a dll to GAC on a Windows Server 2008 machine and kept getting "Access Denied" message.

After fighting with the message for a while and playing with some settings figured the solution. Turning off User Access Control solves the problem. Steps to turn off User Access Control are:
1. Go to Control Panel --> User Accounts
2. Click on "Turn User Account Control On or Off" link
3. Uncheck "Use User Account Control(UAC) to help protect your computer" and Click OK.