Error in Converting a Local Assembly to Shared Assembly

Question

While Converting the Local Assembly to Shared Assembly using Visual Studio Command Prompt using GACUTIL /I <assembly name.dll> I am getting the Following Error

Failure Adding Assembly to the Cache: Administrator Permissions are Needed to use the selected options.Use an Administrator Command Prompt to Complete These Tasks

Please Find me a Solution for this issue & also please tell me the procedure for creating a shared assembly from the local assembly created in Visual Studio 2010 with the help of Class Library