If water is seeping in from the outside then the problem needs to be addressed from the outside. Water getting into the block cannot be stopped with an interior vapor barrier. The waterproofing on the outside of the blockwork either was not applied properly or has been comprimised somehow. you do not want to trap water behind any type of wall you are putting up. Vapor barriers are to keep warm moist interior air from condensing in the cooler insulation in the walls.