Sorry, bit slowing getting back to you.
I know this may be a challenging question, but have you consulted the manual for Ghost? Here are a couple of links that will help you if the documentation is not to hand:
https://support.symantec.com/en_US/article.HOWTO48877.html
ftp://ftp.symantec.com/public/english_us_canada/products/symantec_ghost_solution_suite/2.5/manuals/Ghost_imp_guide.pdf
Having established that you are using Ghost 2.51, are you using a DOS or WinPE boot environment? DOS is realistically not able to handle SATA disks or really large disks, so I'm going to assume you are using WinPE. If you are working with the version of WinPE shipping in Ghost 2.51, it is based on the Vista kernel so will need you to supply Vista 32 bit drivers for the SATA chipset in your machine. Without this, the Ghost program will not be able to "see" the hard disk to make a working image.
Ghost can be started and used interactively from a WinPE command line, so you don't necessarily need to work with command line switches.
I don't specifically know the details of your machines, but if they have a UEFI bios, you need to turn off UEFI before imaging, both on backup and on restore. Ghost 2.51 does not support UEFI due to its age hence the need to turn it off. Also, I cannot recall whether it supports Advanced Format hard disks or not - I think it doesn't, so it's really something for you to check out hardware-wise.
Be aware that Ghost has recently been released in a much updated version - now at 3.1, and is more compatible with modern hardware in a lot of ways. There were also several hotfixes to 2.51 which you can find out more about in the sticky posting at the top of this forum, but can be difficult to get hold of if you don't have a current maintenance agreement.
Personally, I have been using Paragon Partition Manager 15 in recent times as it's both low cost and bang up to date. You can find it here:
http://www.paragon-software.com/home/pm-personal/eshop.html
Ultimately, it all depends on whether your needs are corporate or more "domestic".