Index: Lib/urllib.py
===================================================================
--- Lib/urllib.py	(revision 69418)
+++ Lib/urllib.py	(working copy)
@@ -640,6 +640,8 @@
         fp.close()
         # In case the server sent a relative URL, join with original:
         newurl = basejoin(self.type + ":" + url, newurl)
+        # be conciliant with URIs containing a space
+        newurl = newurl.replace(' ', '%20')
         return self.open(newurl)
 
     def http_error_301(self, url, fp, errcode, errmsg, headers, data=None):