We develop n-cluster mean-field theories (1 < or = n < or = 4) for calculating the flux and the gap distribution in the nonequilibrium steady states of the Katz-Lebowitz-Spohn model of the driven diffusive lattice gas, with attractive and repulsive interparticle interactions, in both one and two dimensions for arbitrary particle densities, temperature as well as the driving field. We compare our theoretical results with the corresponding numerical data we have obtained from the computer simulations to demonstrate the level of accuracy of our theoretical predictions. We also compare our results with those for some other prototype models, notably particle-hopping models of vehicular traffic, to demonstrate the qualitative features we have observed in the Katz-Lebowitz-Spohn model, emphasizing, in particular, the consequences of repulsive interparticle interactions.