The usual.
diff --git a/Lib/dos-8x3/rlcomple.py b/Lib/dos-8x3/rlcomple.py
index e0ae72c..92633ab 100644
--- a/Lib/dos-8x3/rlcomple.py
+++ b/Lib/dos-8x3/rlcomple.py
@@ -58,7 +58,10 @@
                 self.matches = self.attr_matches(text)
             else:
                 self.matches = self.global_matches(text)
-        return self.matches[state]
+        try:
+            return self.matches[state]
+        except IndexError:
+            return None
 
     def global_matches(self, text):
         """Compute matches when text is a simple name.