Mixed system upgrade

[recvfrom@gmail.com]

Hi,

I'm using a mixed system so that I could support
libapache-mod-security.  This was all working fine for some time, but
now an 'apt-get upgrade' results in:

dpkg: error processing
/var/cache/apt/archives/coreutils_7.4-2_i386.deb (--unpack):
 trying to overwrite `/usr/share/man/man1/arch.1.gz', which is also in
package util-linux
dpkg-deb: subprocess paste killed by signal (Broken pipe)
Errors were encountered while processing:
 /var/cache/apt/archives/coreutils_7.4-2_i386.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)

Can anyone point in the right direction to correct this?

My /etc/apt/preferences:

Package: *
Pin: release a=stable
Pin-Priority: 700

Package: *
Pin: release a=testing
Pin-Priority: 650

Package: *
Pin: release a=unstable
Pin-Priority: 600

My /etc/apt/sources.list:

deb http://security.debian.org/ etch/updates main
deb http://ftp.debian.org/debian etch main

#Testing
deb http://ftp.debian.org/debian testing main
#Unstable
deb http://ftp.debian.org/debian unstable main