diff --git a/src/signal/signal-caster.cpp b/src/signal/signal-caster.cpp
index 8a9198660699a63ce3596782e4d3ad10b5e18ebc..dda2e34e01c9c507179844f63cfa592c644720b0 100644
--- a/src/signal/signal-caster.cpp
+++ b/src/signal/signal-caster.cpp
@@ -70,7 +70,10 @@ any SignalCaster::cast(const type_info& type, istringstream& iss) {
 	map<string, cast_functions_type>::iterator it =	functions_.find(type_name);
 
 	if ( it == functions_.end() )
-		throw ExceptionSignal(ExceptionSignal::BAD_CAST, "bad cast");
+	  {
+	    throw ExceptionSignal(ExceptionSignal::BAD_CAST,
+				  "caster not in functions_ map.");
+	  }
 	//TODO: throw "cast not registered" exception
 	return (*it).second.get<1>()(iss); // call cast function (tuple index 1)
 }