Symantec Ghost Solution 12 is not a version number I recognise. The current version of Ghost Solution Suite is 11.5.1.2266.
Are you perchance using the Norton Ghost retail product? Although this has been at version 15 for a long time, it is actually based on different technology to Ghost Solution Suite, and is also supported in a different forum to which you can find a link in the sticky posting at the top of this forum.
In order for anyone in either forum to be able to help you further, once a version has been established, you should also include full details of your hardware, whether the Linux partition is the only one on the hard disk or whether there are any boot managers. Are you repartitioning the drive before re-imaging?
What command line options, or settings, are you choosing when making the image. I suspect you should be using settings which capture the raw data rather than imaging on a file basis as Linux typically does not use a FAT or NTFS file system. For confirmation also, can you specify exactly which file system you are using on the Unbuntu partition. (ext-3, ext-4 ?)