diff --git a/eo/src/utils/eoGnuplot1DMonitor.h b/eo/src/utils/eoGnuplot1DMonitor.h
index e7550875..ac5bfc80 100644
--- a/eo/src/utils/eoGnuplot1DMonitor.h
+++ b/eo/src/utils/eoGnuplot1DMonitor.h
@@ -103,7 +103,7 @@ inline void  eoGnuplot1DMonitor::FirstPlot()
 {
   if (vec.size() < 2)
     {
-      throw runtime_error("Must have some stats to plot!\n");
+      throw runtime_error("eoGnuplot1DMonitor needs at least 2 stats (X and Y)!\n");
     }
   char buff[1024];
   ostrstream os(buff, 1024);