Unfortunately I can't seem to duplicate this with the SBIG sim. Previously, 2.5.1.15, I could replicate the crash pretty much on command. However I can't seem to trigger any error in 2.5.1.16. I'm not really sure what could be all that different that you're seeing considerably worse behavior with .16. The change was actually pretty minor between the two and just involved setting our internal camera status to "IDLE" rather than "ImageReady" after an image had been downloaded.
I'll pull my STL-11000 in and see if I can duplicate with actual hardware. However if it's a download speed issue the STL certainly won't duplicate the issue...
Thanks,
Jared