After leaving a Z-CORP machine for a while, the first thing to do is to clean everything:

Take all the tubes off and blow/rinse them out (or swap them out.)
Clean the Z axis screw with a wire brush.
Clean the x and y axis rails rigorously with paper towels.
There's often build up for dirt in the bearings on the rails (you can take them a part and clean properly.) or pick out with dentist tools.

The Error 1003 (it may be the first of many that you will experience before getting it to run,) is to do with the electrical connection between the cartridge and the machine. Clean the pogo pins with isopropanol or similar and hope that it sorts the problem. If it doesn't then your machine may have a hardware problem...

Before deciding that the machines broke I'd also try a few new print-heads... They are all out of date now and probably only 2/3 new one's still work (though I actually found the older the better.)

They can be quite frustrating to get working, but once you've sorted all the problems, as long as use it semi-regularly and keep it clean they work a treat.