I had the same thing happen, as well as several dependancy issues that took 
some forcing to get past.  I think there is some package that dosnt depend 
just on the 2.4.18 kernel, but for whatever reason depends on the smp one.  I 
have never noticed much of a difference in performance between the SMP and 
non-SMP kernels on my workstations, so I dont view it as a big deal.

On Wednesday 05 June 2002 04:16 pm, Amy Tanner wrote:
> I'm testing using apt-get dist-upgrade to upgrade my RH 7.2 boxes to
> 7.3.  When I did this, I noticed in the list of NEW packages to be
> installed, it listed kernel-smp#2.4.18-4.  These are single CPU boxes,
> so I'm wondering why it would do that.  I got around it by manually
> installing the new kernel.
>
> apt-get install kernel#2.4.18-4
>
> My apt.conf looks like this:
>
> RPM
> {
>    // Leave list empty to disable
>    AllowedDupPkgs {"^kernel$"; "kernel-smp"; "kernel-enterprise"; };
>    HoldPkgs {"kernel-source"; "kernel-headers"; };
> }
>
> I currently have 2.4.9-31 kernel installed:
>
> # rpm -qa|grep ^kernel
> kernel-source-2.4.9-31
> kernel-2.4.9-31
> kernel-headers-2.4.9-31
> kernel-doc-2.4.9-31
>
> Any ideas?