>> I don't have a /etc/apt/sources.list.d/centos.list
>>
>
> Do you have the apt provided by centos ... or from another vendor?
>
> What does this say:
>
> rpm -q apt
>
> The result should be:
>
> apt-0.5.15cnc6-4.centos4.i386
>
> If you have someone else's apt, it erased our configuration file.
I remember now from a previous thread on this. The dag repo replaced the
centos apt with
apt-0.5.15lorg3.1-1.el4.rf
What I've been doing lately is using
yum upgrade
to keep my system up to date, and only occasionally using Synaptic. But I
prefer the Synaptic interface a lot more.