Klocwork made another run and found a bunch more problems.
This is the first batch of fixes that should be easy to verify based on context.

This fixes problem numbers: 220 (ast), 323-324 (symtable),
321-322 (structseq), 215 (array), 210 (hotshot), 182 (codecs), 209 (etree).
diff --git a/Python/ast.c b/Python/ast.c
index ca832aa..b356192 100644
--- a/Python/ast.c
+++ b/Python/ast.c
@@ -2197,6 +2197,8 @@
             }
             else {
                 alias_ty a = alias_for_import_name(c, CHILD(n, 0));
+                if (!a)
+                    return NULL;
                 if (strcmp(STR(CHILD(n, 1)), "as") != 0) {
                     ast_error(n, "must use 'as' in import");
                     return NULL;
diff --git a/Python/symtable.c b/Python/symtable.c
index 439a243..3e58b50 100644
--- a/Python/symtable.c
+++ b/Python/symtable.c
@@ -915,6 +915,8 @@
 	PyOS_snprintf(tmpname, sizeof(tmpname), "_[%d]",
 		      ++st->st_cur->ste_tmpname);
 	tmp = PyString_InternFromString(tmpname);
+	if (!tmp)
+		return 0;
 	if (!symtable_add_def(st, tmp, DEF_LOCAL))
 		return 0;
 	Py_DECREF(tmp);
@@ -1323,8 +1325,11 @@
 	PyObject *name = (a->asname == NULL) ? a->name : a->asname;
 	const char *base = PyString_AS_STRING(name);
 	char *dot = strchr(base, '.');
-	if (dot)
+	if (dot) {
 		store_name = PyString_FromStringAndSize(base, dot - base);
+		if (!store_name)
+			return 0;
+	}
 	else {
 		store_name = name;
 		Py_INCREF(store_name);