source_wrapper.pl: imporved error messages
source_wrapper.pl: imporved error messages

junghans/csg,MrTheodor/csg,votca/csg,richardjgowers/csg,junghans/csg,richardjgowers/csg,votca/csg,MrTheodor/csg,MrTheodor/csg,junghans/csg,junghans/csg,MrTheodor/csg,junghans/csg,richardjgowers/csg,votca/csg,richardjgowers/csg,votca/csg,richardjgowers/csg,MrTheodor/csg,junghans/csg