Index: complete.el
===================================================================
RCS file: /cvsroot/emacs/emacs/lisp/complete.el,v
retrieving revision 1.78
diff -p -u -w -r1.78 complete.el
--- complete.el	26 Aug 2007 19:20:10 -0000	1.78
+++ complete.el	6 Sep 2007 04:49:05 -0000
@@ -596,9 +596,10 @@ GOTO-END is non-nil, however, it instead
           (setq poss (all-completions (if env-on basestr str)
 				      table
 				      pred))
-          (unless poss
+          (unless (or poss (string-equal str ""))
             ;; Try completion as an abbreviation, e.g. "mvb" ->
-            ;; "m-v-b" -> "multiple-value-bind"
+            ;; "m-v-b" -> "multiple-value-bind", but only for
+            ;; non-empty strings.
             (setq origstr str
                   abbreviated t)
             (if filename