dchroot doesn't know user

[rainer herrendoerfer <rainer.2@tiscali.de>]

Hello list,
I just try installing a new pure64. According to the HOW-TO on
https://alioth.debian.org/docman/view.php/30192/21/debian-amd64-howto.html#id274383
it's possible to run 32bit programms as chroot (from root via su).
When i try to run them from a normal user account I get the following 
error message:

raina:~$ dchroot -c ia32 -d firefox
   (ia32) firefox
   Unknown ID: raina
   dchroot: Child exited non-zero.
   dchroot: Operation failed./
/ 
Any ideas????

Thanks in advance

Rainer