Dear Helpers - Era, Reto, Bennett, David and Martin!
It finally works because of your great help!
My .rc-file now looks like this:
:0
* >50000
{
:0c
! flittermice(_at_)lion(_dot_)cc
:0fhw
| /usr/local/bin/formail -I Content-Type:
:0bfi
| cat $HOME/Procmail/notification
:0:
$DEFAULT
}
The thing was that the mail-clients seem to have a problem with the
"Content-Type:" headerfield if there was something like "multipart" or
similar. After I removed this header field, everything worked fine -
no, not everything: I had to write the absolute path to formail
because it was not found by the shell.
Thanks to all and best regards
Armin