error 1015 in itunes

Dear all pls I really need help iv got a mint condition iphone 3g or 3gs im not sure the model no is a1241 I reset it to its factory settings from settings general and erase all contents and settings after that its stucks on apple logo and iTunes logo I tried several methods but nothing happen in iTunes its telling me error 1015 pls I need help is there anything to do? or I thru it away?