Current - voltage characteristics are reported for a thin film with a granular structure. Our data provide support for a Berezinskii - Kosterlitz - Thouless transition type with an unusual vortex - antivortex interaction . Dissipation is discussed in terms of large-scale pair excitations through the sample inhomogeneities. Consistency is found with the theory worked out by Lobb, Abraham and Tinkham to explain resistive transition data in arrays of superconducting junctions arranged two-dimensionally. On this basis, the temperature behaviour of A(T) accounts for a weakening of the pair potential at interfaces due to the short coherence length of high- oxides, as was pointed out by Deutscher and Müller. We investigate the spatial renormalization of the vortex - antivortex interaction over the length scale probed by the current in the same manner as was first demonstrated by Kadin, Epstein and Goldman. Then good agreement with the renormalized Kosterlitz - Thouless theory is found.