A Freedom Airline Fokker 50 sustained substantial damage in an accident on the apron at Nairobi-Jomo Kenyatta International Airport (NBO/HKJK). The crew ferried the aircraft from Nairobi-Wilson to NBO and on arrival, the aircraft was taxied to terminal 2-M22 where the chocks were placed and the Ground Power Unit connected. The captain reported that the crew then disembarked to perform walk rounds as per the relevant checklist from which no anomalies were reported. The flight crew then proceeded to do their briefing with the ground handling personnel and gave the boarding clearance. On completion, the captain reported, having obtained the engine start clearance and requested the ground handlers to remove the GPU and the chocks. The GPU was, however, not clear at the time the aircraft began taxiing and consequently, the aircraft engine no.2 propeller impacted the GPU, causing the separation of two propeller blades and damage to the remaining four blades. Shrapnel penetrated the fuselage above RH window number 5. The Captain immediately shut down the engines and commanded the cabin crew to evacuate the passengers to the terminal building as per emergency evacuation procedures. The aircraft sustained substantial damage to its RH Engine and shrapnel penetrated the upper part of the fuselage above the RH window NUMBER 5. The GPU was damaged and no injuries were reported .