This is not a Qimage issue. If Qimage's processing bar on the lower right reaches 100% (which it would have if the printer started printing), Qimage has sent all the data to the printer. If you get partial prints at that point, we have to fix the issue with your system. The demo and the registered version have the same code for printing so if the demo worked, I can only guess that you were printing smaller photos with the demo and the larger ones are causing a system problem where the system is unable to handle the larger amount of data. Qimage can sometimes expose system issues because it sends more data than most printing programs: ones that don't bother to interpolate or match driver resolution.
I see that you are printing via the network. That adds an extra layer of data transfer since you are now relying on at least 2 PC's to be configured properly for large data transfers, network queue sizes, etc. If you are able, you might want to connect the printer to the PC where you are using Qimage (via USB) and see if that solves the problem. If so, at least we'll know to look in the area of LAN data transfer or memory limitations on the network attached PC.
Since you have a large format printer and you are printing across a network, also take a look at this troubleshooting article that addresses some of these data transfer issues:
http://ddisoftware.com/tech/articles/april-2006-houston-we-have-a-(printing)-problem/See the section on partial prints near the bottom.
Edit: I also just noticed that your driver says "HP DesignJet Z3200 44in Class Driver". I've not seen that before. Typically if you've installed the printer driver from HP, the printer name will be "HP DesignJet Z3200 44in Photo PCL3". I'm concerned that you let Windows install some Microsoft driver and if so, that can cause problems too. You never want to accept the OS drivers: download and install them from HP. The same is true on the Mac: the most common problem on the Mac is trying to use Apple's "AirPrint" drivers from the OS. It's a similar situation with Windows, particularly when printing to a network printer because Windows will ask you if you want to install a driver automatically.
Regards,
Mike