--- a/interpreter/api/ThreadContextStubs.cpp
+++ b/interpreter/api/ThreadContextStubs.cpp
@@ -576,7 +576,7 @@
     catch (RexxNativeActivation *)
     {
     }
-    return false;
+    return NULL;
 }
 
 
@@ -591,7 +591,7 @@
     catch (RexxNativeActivation *)
     {
     }
-    return false;
+    return NULL;
 }