amount of time needed to finish image

I'm using Snap Deploy build 2105 to Dell Optiplex 745 pc's, the OS is Windows XP SP2, and we are in a Windows Domain.

How much time should it take (roughly) to image a pc from the point where you begin the deployment, to when you can actually login to the new pc?
This will probably depend on the size of the image file, in our case it's 9Gb.

I have imaged 15 Dell pc's and in each case the process of deploying an image took 15 minutes from the start of the process to getting being able to login to the newly imaged computer. 10 minutes to copy the image to the pc's and then 5 minutes and 2 or 3 reboots where the Snap Deploy is configuring each system with the specified deployment options....

However, now any pc's that I try to image either just sit at a blue screen with an arrow cursor for hours at a time, or I get a message that ds_gina.dll is missing or corrupt. I have not changed the image at all, or the physical environment (cables, switch, etc) where I'm doing the imaging. This has happened with 6 different pc's so far. I've purchased 30 licenses, so I don't think it's a licensing issue. Although the license server shows I've used 23 licenses even though I've only imaged 15 pc's successfully.