Index: trunk/FACT++/scripts/Observation_class.js
===================================================================
--- trunk/FACT++/scripts/Observation_class.js	(revision 17188)
+++ trunk/FACT++/scripts/Observation_class.js	(revision 17189)
@@ -58,5 +58,5 @@
         case 'DATA':
             if (i!=obj.measurements.length-1)
-                throw new Error("DATA must be the last in the list of measurements");
+                throw new Error("DATA [n="+i+", "+utc.toUTCString()+"] must be the last in the list of measurements [cnt="+obj.measurements.length+"]");
             if (ret[i].source == undefined)
                 throw new Error("Observation must have either 'source' or 'task' " +