diff --git a/version3.0/nasal_gc.h b/version3.0/nasal_gc.h
index 7b77452..bb0ab83 100644
--- a/version3.0/nasal_gc.h
+++ b/version3.0/nasal_gc.h
@@ -1535,7 +1535,7 @@ int nasal_virtual_machine::mem_change(int memory_address,int value_address)
     else
     {
         if(error_info_output_switch)
-            std::cout<<">> [vm] mem_store:unexpected memory \'"<<memory_address<<"\'."<<std::endl;
+            std::cout<<">> [vm] mem_change:unexpected memory \'"<<memory_address<<"\'."<<std::endl;
         return 0;
     }
     return 1;
@@ -1549,7 +1549,7 @@ int nasal_virtual_machine::mem_init(int memory_address,int value_address)
     else
     {
         if(error_info_output_switch)
-            std::cout<<">> [vm] mem_store:unexpected memory \'"<<memory_address<<"\'."<<std::endl;
+            std::cout<<">> [vm] mem_init:unexpected memory \'"<<memory_address<<"\'."<<std::endl;
         return 0;
     }
     return 1;
diff --git a/version3.0/nasal_runtime.h b/version3.0/nasal_runtime.h
index 5449882..0cba470 100644
--- a/version3.0/nasal_runtime.h
+++ b/version3.0/nasal_runtime.h
@@ -1172,7 +1172,11 @@ int nasal_runtime::call_scalar_mem(nasal_ast& node,int local_scope_addr)
         }
         mem_address=tmp_mem_addr;
         if(mem_address<0)
+        {
+            ++error;
+            std::cout<<">> [runtime] call_scalar_mem: cannot find correct memory space."<<std::endl;
             break;
+        }
     }
     return mem_address;
 }