Index: b/src/plugins/fits/non_linear_weighted.h
===================================================================
--- a/src/plugins/fits/non_linear_weighted.h
+++ b/src/plugins/fits/non_linear_weighted.h
@@ -193,7 +193,9 @@
           }
           while( iStatus == GSL_CONTINUE && iIterations < MAX_NUM_ITERATIONS );
 
-          gsl_multifit_covar( pSolver->J, 0.0, pMatrixCovariance );
+          gsl_matrix *J = gsl_matrix_alloc (pSolver->fdf->n, pSolver->fdf->p);
+          gsl_multifit_fdfsolver_jac (pSolver, J);
+          gsl_multifit_covar (J, 0.0, pMatrixCovariance);
 
           //
           // determine the fitted values...
--- Kst-2.0.8/src/plugins/fits/non_linear.h.orig	2016-01-25 21:30:09.472476599 -0500
+++ Kst-2.0.8/src/plugins/fits/non_linear.h	2016-01-25 21:34:01.081715024 -0500
@@ -177,7 +177,9 @@
             }
             iIterations++;
           } while( iStatus == GSL_CONTINUE && iIterations < MAX_NUM_ITERATIONS );
-          gsl_multifit_covar( pSolver->J, 0.0, pMatrixCovariance );
+          gsl_matrix *J = gsl_matrix_alloc (pSolver->fdf->n, pSolver->fdf->p);
+          gsl_multifit_fdfsolver_jac (pSolver, J);
+          gsl_multifit_covar (J, 0.0, pMatrixCovariance);
 
           //
           // determine the fitted values...