diff -u pcp8/pcpi.py pcp9/pcpi.py
--- pcp8/pcpi.py	2009-05-13 21:28:53.000000000 -0400
+++ pcp9/pcpi.py	2009-05-14 22:10:18.000000000 -0400
@@ -227,7 +227,7 @@
         i = core.desc.indom
         if not self._mcIndomD.has_key( i ):
             if i == PM_INDOM_NULL:
-                self._mcIndomD.update( { i : {-1:"(null)"} } )
+                self._mcIndomD.update( { i : { PM_IN_NULL : "(null)" } } )
             else:
                 instL, nameL = self.pmGetInDom( i )
                 d = dict( zip( instL, nameL ) )
diff -u pcp8/pmapi.c pcp9/pmapi.c
--- pcp8/pmapi.c	2009-05-13 21:28:53.000000000 -0400
+++ pcp9/pmapi.c	2009-05-14 22:08:44.000000000 -0400
@@ -105,7 +105,7 @@
 
     dict_add_uint( dict, "PM_ID_NULL", PM_ID_NULL );
     dict_add_uint( dict, "PM_INDOM_NULL", PM_INDOM_NULL );
-    dict_add_uint( dict, "PM_IN_NULL", PM_IN_NULL );
+    dict_add_int( dict, "PM_IN_NULL", PM_IN_NULL );
 
     dict_add_uint( dict, "PM_NS_DEFAULT", (unsigned int) PM_NS_DEFAULT );