Testing on Windows XP SP3, JDK v1.6.0 update 23, Android SDK rev9, AShot v1.1 and using a Samsung Epic 4G (SPH-D700) w/ Samsung drivers v1.3.8 :
After troubleshooting why ddms.bat couldn't recognize my phone, I was able to finally get it to connect. (The install directions on the main webpage have nothing about adding the Java bin to environment variables. Found that tid-bit in the comments.) I was able to get AShot working. About 2 minutes after playing around in full screen mode, I got a crash notice from Windows. The attached file is the crash dump.
Please investigate the reason for this crash, as it stands I cannot utilize this tool for phone demonstration purposes. :-\