Single molecule spectroscopy shows that line shapes of guest molecules in low-temperature disordered solids vary from one molecule to the other. We consider a single molecule in a host lattice interacting with randomly distributed two level defects via a long range interaction. We investigate in detail the dipolar interaction and calculate the probability density of variances for high and low densities of defects. (C) 1999 Published by Elsevier Science B.V. All rights reserved.