--- a/hgext/convert/cvs.py	Wed Jul 08 23:17:10 2009 +0200
+++ b/hgext/convert/cvs.py	Wed Jul 08 22:08:45 2009 -0400
@@ -282,7 +282,9 @@
         self.writep.flush()
         r = self.readp.readline()
         if not r.startswith("Valid-requests"):
-            raise util.Abort(_("server sucks"))
+            raise util.Abort(_("unexpected response from CVS server "
+                               "(expected \"Valid-requests\", but got %r)")
+                             % r)
         if "UseUnchanged" in r:
             self.writep.write("UseUnchanged\n")
             self.writep.flush()