Summers rpm failure

[Martin]

Hello.

At this point :-

This creates three Qmail RPMs in /usr/src/redhat/RPMS/i386. The only one you
are interested in is qmail-1.03-6.i386.rpm, you don't need the other two. Now
      let's install it:

        $ rpm -U /usr/src/redhat/RPMS/i386/qmail-1.03-6.i386.rpm

it fails with   'failed dependencies: sendmail conflicts with qmail-1.03-6'

Why is this ??

Regards...Martin