What does this mean?

Hi 

I just compiled the latest version of procmail from the Aachen
ftp-server. I just send myself an email to test it. Everything works
fine, but there's this error-message I don't understand:
 procmail: Couldn't determine implicit lockfile from "formail"
 formail: formail cannot open (or something like that follows).
What did I do wrong when Icompiled everything, or is it something
else?

     _/_/_/ _/_/_/_/  _/_/                     Andreas Sikkema
   _/    _/   _/   _/                      sikke600(_at_)tem(_dot_)nhl(_dot_)nl
  _/_/_/_/   _/     _/_/   Maintainer of the NS-Discussies FAQ
 _/    _/   _/         _/                                     
_/    _/   _/    _/_/_/   www.engineering.tem.nhl.nl/~sikke600