--- src/allmydata/frontends/ftpd.py.org	Sat Jan 23 15:16:36 2010
+++ src/allmydata/frontends/ftpd.py	Sat Jan 23 15:18:37 2010
@@ -289,7 +289,7 @@
         # make sure we're using a patched Twisted that uses IWriteFile.close:
         # see docs/frontends/FTP-and-SFTP.txt and
         # http://twistedmatrix.com/trac/ticket/3462 for details.
-        assert "close" in ftp.IWriteFile.names(), "your twisted is lacking"
+        assert "close" in ftp.IWriteFile.names(), "your twisted is lacking a vital patch, see docs/frontends/FTP-and-SFTP.txt"
 
         r = Dispatcher(client)
         p = portal.Portal(r)