The CodeBench Getting Started Guide System Requirements section covers all "officially supported/tested" operating systems which does not include Windows 8 at this time. So if you try and it works, that is good. But we cannot claim to have tested (or support) that combination.
This version of Sourcery CodeBench supports the following host operating systems and architectures:
Microsoft Windows XP (SP1), Windows Vista, and Windows 7 systems using IA32, AMD64,
and Intel 64 processors.
GNU/Linux systems using IA32, AMD64, or Intel 64 processors, including Debian 5 (and later),
Red Hat Enterprise Linux 5 (and later), SuSE Enterprise Linux 10 (and later), and Ubuntu 8.04
Sourcery CodeBench is built as a 32-bit application. Therefore, even when running on a 64-bit host
system, Sourcery CodeBench requires 32-bit host libraries. If these libraries are not already installed
on your system, you must install them before installing and using Sourcery CodeBench. Consult
your operating system documentation for more information about obtaining these libraries.