diff --git a/common/source/java/ch/systemsx/cisd/common/evaluator/Evaluator.java b/common/source/java/ch/systemsx/cisd/common/evaluator/Evaluator.java
index 0fe4049611c79da0a0c382128dedd1f39d5ffbd7..02770122f22f38292b7ed3b1cf9c87d66c4d386b 100644
--- a/common/source/java/ch/systemsx/cisd/common/evaluator/Evaluator.java
+++ b/common/source/java/ch/systemsx/cisd/common/evaluator/Evaluator.java
@@ -366,7 +366,7 @@ public final class Evaluator
         } catch (ClassCastException ex)
         {
             final ReturnType type = getType();
-            throw new EvaluatorException("Expected a result of type " + ReturnType.INTEGER
+            throw new EvaluatorException("Expected a result of type " + ReturnType.BOOLEAN
                     + ", found " + type);
         }
     }