In Zope 2.4, the ExtensionClass.h file has moved into a src subdirectory. Therefore, the Setup file of ZPatterns needs to change from this: *shared* DynPersist DynPersist.c -I../../ZODB \ -I../../../Components/ExtensionClass to this *shared* DynPersist DynPersist.c -I../../ZODB \ -I../../../Components/ExtensionClass/src -- Steve Alexander