Here is the patch for pg_dump not handling NULL values in 'insert'

mode properly.  This will apply correctly to 1.09 & 2.0 sources.
From David H. Bennett

src/bin/pg_dump/pg_dump.c

@@ -20,7 +20,7 @@
  *
  *
  * IDENTIFICATION
- *    $Header: /cvsroot/pgsql/src/bin/pg_dump/pg_dump.c,v 1.15 1996/11/17 04:56:01 momjian Exp $
+ *    $Header: /cvsroot/pgsql/src/bin/pg_dump/pg_dump.c,v 1.16 1996/11/20 22:32:55 momjian Exp $
  *
  * Modifications - 6/10/96 - dave@bensoft.com - version 1.13.dhb
  *
@@ -1456,6 +1456,10 @@ dumpClasses(TableInfo *tblinfo, int numTables, FILE *fout, const char *onlytable
 		    fprintf(fout, "values (");
 		    field=0;
 		    do {
+			if (PQgetisnull(res,tuple,field)) {
+                            fprintf(fout,"NULL");
+			}
+                    	else {
 			    switch(PQftype(res,field)) {
 			    	case 21: case 22: case 23: /* int types */
 			    	case 810: case 910: /* oldint types */
@@ -1482,6 +1486,7 @@ dumpClasses(TableInfo *tblinfo, int numTables, FILE *fout, const char *onlytable
 			            fprintf(fout, "'%s'", expandbuf);
 			            break;
 		            }
+		        }
 		        field++;
 		        if(field != PQnfields(res))
 			    fprintf(fout, ",");