User Portlet

I am trying to build a small macro to get the memory used by Global Variables in a scrip , i tried an expression like this

Map[Length, Names["Global`*"]]

however the output is zeros only

when i try

Map[ByteCount, Names["Global`*"]]

it also does not seem to return sensible numbers [they all are 40]. it does seem that the expression is evaluate in the wrong context however it isn't obvious to me why or how

thanks a lot for any help , Bernd