have any example on varyBycustomParam, VaryByHeader, VaryByQuery string custom parameter passing technique?

regarding to above question we have tried for custom parameter passing through cache profile creation using asp.net code but in register assembly in global.aspx it will give error like "NameSpace can not be loaded" error in web.config files. i have also given safe control with assembly name and token id of asp.net code .dll till it will show same error

Please reply as early as possible.