Employee (EE) climbed over platform guardrail onto raised forklift carrying screens, EE and screens fell from forklift 15 to 17 ft; EE landed on his feet, knees buckled, he collapsed to the ground & apparently one or more screens fell onto employee's body-trunk area abdomen region. Co-worker & injured worker moved screen(s) off of EE & EE scooted himself away from screens.