How to delete a uid from a secret key?

[Sebastian Dietrich]

Hello,

I have a UID in my secret key, which actually is the name and email of a friend of mine. So it has 
to be removed from there. But when I say "deluid", GnuPG tells me to toggle. But the UID is not in 
my public key, it is in my secret key! How can I remove this UID?

Thanks for your help in advance

Sebastian

PS: Here is the output of a session (email-adresses and names changed to dummy values):

C:\Programme\gnupg-w32-1.0.6>gpg --edit-key 5915B73A
gpg (GnuPG) 1.0.6; Copyright (C) 2001 Free Software Foundation, Inc.
This program comes with ABSOLUTELY NO WARRANTY.
This is free software, and you are welcome to redistribute it
under certain conditions. See the file COPYING for details.

Secret key is available.

pub  1024D/5915B73A  created: 2001-12-09 expires: never      trust: -/u
sub  2048g/FFA5BC7E  created: 2001-12-09 expires: never
(1). Mister X <me at inter.net>

Command> toggle

sec  1024D/5915B73A  created: 2001-12-09 expires: never
ssb  2048g/FFA5BC7E  created: 2001-12-09 expires: never
(1)  Mister X <me at inter.net>
(2)  Mister Y <a_friend at inter.net>

Command> uid 2

sec  1024D/5915B73A  created: 2001-12-09 expires: never
ssb  2048g/FFA5BC7E  created: 2001-12-09 expires: never
(1)  Mister X <S.Dietrich at gmx.de>
(2)* Mister Y <a_friend at inter.net>

Command> deluid
Please use the command "toggle" first.

Command> toggle

pub  1024D/5915B73A  created: 2001-12-09 expires: never      trust: -/u
sub  2048g/FFA5BC7E  created: 2001-12-09 expires: never
(1). Mister X <me at inter.net>

Command> deluid
You must select at least one user ID.