If you are getting the following message, your stock coordinates have been set incorrectly:
In the example below, the -Z dimension is 4" which would put it above the +Z dimension and would result in this error message. The correct value in this case would be -4. The same conflict can occur of any of the other axes.
To fix this error open the Documents dialog located on the top right side of your screen. This is where Stock definition is entered as well as other machining parameters. Go through each of the values entered in the stock definition dialog boxes. The most common error is a missing negative symbol in one of the fields