In order to capture an image of a machine that is not running its operating system, the machine has to be booted to another operating system that can access the hard disk and the network (if imaging over the network), and with modern hardware, that would be WinPE rather than DOS. Since the version of WinPE supplied with Ghost is based on the Vista kernel, you need to add Vista 32 bit drivers for your hardware.
You could of course boot WinPE locally, run ghost from your WinPE boot media and image to a local USB hard disk, which would avoid having to support network connectivity, but you still need to build a WinPE boot image.
These articles may help, but there is no real substitute for reading the documention as well.
http://www.symantec.com/business/support/index?page=content&id=TECH110134&profileURL=https%3A%2F%2Fsymaccount-profile.symantec.com%2FSSO%2Findex.jsp%3FssoID%3D1379325844236H648XIOBo89QYnlyyqy8JBXy4XpzTOpCi8Nmu
https://www-secure.symantec.com/connect/articles/do-i-have-correct-driver-winpe
To get independent experience of WinPE, you can build your own version using this article:
http://www.symantec.com/connect/articles/readyadventures-winpe
In order to image machines without running a local operating system, you can use PXE boot to load the necessary WinPE image over the network, but this also requires you to set up a PXE server as part of your Ghost server environment. There are articles on this too, which you can find using the forum search engine. Here is a typical article: http://www.symantec.com/business/support/index?page=content&id=TECH110129