Hey, Jack, I just saw your post - sorry, I've been busy the last few days, and haven't checked for new messages. If you have the zt-update in the root of your SD card, and the files ZT280.kernel, ZT280.recovery and ZT280.system are all in that directory, then it should work - are you pressing the camera button, then while holding the camera button pressing and holding the power button until the screen comes on? some of these tablets are sensitive in that way. Once the screen comes on, it should either just go into update mode or ask you to press the camera button again, to continue with the update. It *IS* important to not touch the screen during the loading process - it will do strange and unknown things to you if you do.
I just loaded up a new version of ICS, BTW - it's dated 20120206 - less problems in that load - I have it hacked to 900MHz, and will share with you the instructions for doing this, if you get it to load. Tom