diff --git a/source/ps/Singleton.h b/source/ps/Singleton.h
index e120039600..424107a700 100755
--- a/source/ps/Singleton.h
+++ b/source/ps/Singleton.h
@@ -20,6 +20,7 @@
 #define _TEMPLATE_SINGLETON
 
 #include <assert.h>
+#include "types.h"	// uintptr_t - not otherwise defined by VC6
 
 
 template<typename T>