There are a number of possible issues here, but for a start, have you read this KB article:
http://www.symantec.com/business/support/index?page=content&id=HOWTO42361&actp=search&viewlocale=en_US&searchid=1326355131481 ??
It would be helpful to know exactly which build of Ghost Solution Suite you are using, and which operating system you are imaging. In addition, what hardware are you using to host the image, and what bios version?
Are you using the reboot command in your Ghost string? Are you using WinPE?
Failure to reboot can sometimes be a bios issue, or hardware related, so if you have any different hardware platforms you could test on, that would help exclude the particular machine you are using for testing at the moment.