so it looks like it can find the base64 stuff okay, but it does bad
things.

I changed my load-path so that it found the ognus/contrib dir before
the tramp/lisp dir, but it made no difference.  No wonder:

[~/emacs] erwin1 $ diff tramp/lisp/base64.el ognus/contrib/base64.el 
[~/emacs] erwin1 $