Look in your tool setup screen. The first two columns on the left I think. They should read something like:
Sometimes if ours has a bad alarm or power outage in the middle of program and we start it up these numbers get messed around and it won't grab the right tools. If there is no tool in the spindle, all of the numbers in those two columns should be filled out. If there is a tool in the spindle it will change the number from whatever tool # to zero.
Hope this helps?