Index: trunk/psphot/src/psphotMakeFluxScale.c
===================================================================
--- trunk/psphot/src/psphotMakeFluxScale.c	(revision 20002)
+++ trunk/psphot/src/psphotMakeFluxScale.c	(revision 20003)
@@ -29,16 +29,17 @@
             float y = psImageBinningGetFineY (trend->map->binning, iy + 0.5);
 
+	    float fitSum = 0;
+
             // create normalized model object at xc,yc
             pmModel *model = pmModelFromPSFforXY (psf, x, y, 1.0);
             if (!model) {
-                psError(PS_ERR_UNKNOWN, false, "Unable to generate model for grid point %d,%d", ix, iy);
-                success = false;
-                goto DONE;
-            }
-
-            // measure the fitMag for this model
-            float fitSum = model->modelFlux (model->params);
-            assert (fitSum > 0);
-            assert (isfinite(fitSum));
+                psTrace ("psphot", 3, "Unable to generate model for grid point %d,%d", ix, iy);
+		fitSum = NAN;
+            } else {
+		// measure the fitMag for this model
+		fitSum = model->modelFlux (model->params);
+		assert (fitSum > 0);
+		assert (isfinite(fitSum));
+	    }
 
             xPts->data.F32[Npts] = x;