diff --git a/src/osgPlugins/osga/OSGA_Archive.h b/src/osgPlugins/osga/OSGA_Archive.h
index f00e1c6ca..679b085b5 100644
--- a/src/osgPlugins/osga/OSGA_Archive.h
+++ b/src/osgPlugins/osga/OSGA_Archive.h
@@ -95,7 +95,7 @@ class OSGA_Archive : public osgDB::Archive
   
         mutable osgDB::ReentrantMutex _serializerMutex;
 
-
+    	class IndexBlock;
         friend class IndexBlock;
 
         class IndexBlock : public osg::Referenced