You need to go through the default settings for your Ghost program and change the logfile location to somewhere other than the default A:\
Clearly your imaging is running into an error, and I'm guessing you are trying to image using a DOS boot. From a past posting, I do recall another user reporting that they had found a maximum image size that could be handled with a DOS boot, and it was in the low 20's in Gb, so it is entirely possible that your are also running into this problem. You may need to consider building a WinPE boot environment and running your Ghost executable under WinPE instead of DOS in order to be able to capture such a large image with your very old version of Ghost.