[Pharo-users] Error while loading GitFileTree in Pharo 4.0

Whenever I click on Install stable version of GitFileTree (ThierryGoubier .33) in Configuration Browser in Pharo 4.0 , I get the error = The symbolic version #stable is not defined in Configuration GitFileTree for the current platform. Possible symbolic version values include : #(#bleedingEdge #development) Can anyone please help me out ?