Adrian Aichner writes:
 >
 >   Can't check signature: Public key 82EDF2C1D1DD84CD not found
 
 See package-get-require-signed-base-updates under
 
http://www.xemacs.org/Documentation/packageGuide.html#Installing_automati... 
Ah, thanks! Running 
  gpg --keyserver 
hkp://wwwkeys.pgp.net --recv-key 82EDF2C1D1DD84CD
did the trick.
Sorry to bother you,
Tim