  We investigate numerically the effect of long-range interaction on the
transverse localization of light. To this end, nonlinear zigzag optical
waveguide lattices are applied, which allows precise tuning of the second-order
coupling. We find that localization is hindered by coupling between
next-nearest lattice sites. Additionally, (focusing) nonlinearity facilitates
localization with increasing disorder, as long as the nonlinearity is
sufficiently weak. However, for strong nonlinearities, increasing disorder
results in weaker localization. The threshold nonlinearity, above which this
anomalous result is observed grows with increasing second-order coupling.
