diff --git a/modules/mol/mm/src/simulation.cc b/modules/mol/mm/src/simulation.cc
index 8433735c6af02e6bb757ffcb66fb0ef119ea0716..1dd71dfe867552a1f438384b1148d5c24d9e9010 100644
--- a/modules/mol/mm/src/simulation.cc
+++ b/modules/mol/mm/src/simulation.cc
@@ -35,7 +35,7 @@ void Simulation::Save(const String& filename){
 SimulationPtr Simulation::Load(const String& filename, MMSettingsPtr settings){
   if (!boost::filesystem::exists(filename)) {
     std::stringstream ss;
-    ss << "Could not open topology. File '"
+    ss << "Could not open simulation File '"
        << filename << "' does not exist";
     throw ost::io::IOException(ss.str());
   }