How to disable Kerberos / reset CUPS on OS X?

[matthias]

dear members,

i have a major problem. i activated kerberos using localhost:631 on my macbook - leopard.
i donä use kerberos in any way...i know, stupid idea.
my main problem is, that i am not ableto add or delete a printer since that accident happened. i even can't edit the cupsd.conf file ot set auth type from negotiate back to basic. i always get the error that i am not authorized.

hopefully someone knows how i can fix this.
thanks in advance.