Fullerene (C60 and C70)films were epitaxially grown on fresh (001) mica fcc closely-packed plane parallel to the substrate surface. Metal-overlayers were deposited onto these fullerene films in an ultra-hight-vacuum(UHV) chamber and in situ resistance measurements were performed. With increasing current, we observed reversible resistance variation and irreversible breakdown. Nera the percolation threshold we find power law scaling behavior Ib~R-α,where Ib is breakdown current and R the sample resistance. The exponent α is much smaller than the values given by previous experiments and prediction of conventional Nodes-Links-Blobs(NLB) model. Possible explanation of these phenomena based on metal-fullerene interfacial interactions is discussed.