Get: 1 http://ftp.uk.debian.org testing/main libglitz1 0.5.6-1 [80.4kB]
Get: 2 http://ftp.uk.debian.org testing/main libglitz-glx1 0.5.6-1 [30.2kB]
Fetched 111kB in 0s (470kB/s)
(Reading database ... 132234 files and directories currently installed.)
Unpacking libglitz1 (from .../libglitz1_0.5.6-1_i386.deb) ...
dpkg: error processing /var/cache/apt/archives/libglitz1_0.5.6-1_i386.deb (--unpack):
 trying to overwrite `/usr/lib/libglitz.so.1.0.0', which is also in package glitz
Unpacking libglitz-glx1 (from .../libglitz-glx1_0.5.6-1_i386.deb) ...
dpkg: error processing /var/cache/apt/archives/libglitz-glx1_0.5.6-1_i386.deb (--unpack):
 trying to overwrite `/usr/lib/libglitz-glx.so.1.0.0', which is also in package glitz
Errors were encountered while processing:
 /var/cache/apt/archives/libglitz1_0.5.6-1_i386.deb
 /var/cache/apt/archives/libglitz-glx1_0.5.6-1_i386.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)