Causes of condensation in basement wall
It's the combination of polyethylene and fiberglass batt insulation. What you have there is a mold-and-rot-machine. For more info, see http://www.buildingscience.com/documents/digests/bsd-103-understanding-basements/

You need to remove the poly sheeting at a minimum. Preferably, you would redo the basement wall entirely to have rigid foam insulation against the concrete walls and spray foam in the stud bays of the aboveground part.