You have a
0 in your lists, and
Also, if you remove the
; from the first part, you will see the exact same result.
Additionally, you could use
ParallelMap instead of
Anyway, your code basically says "Calculate 1/x for -1, 0, 1, and 2" and it does so correctly for each case. The error you see just comes from the fact that you're calculating a 1/0 case.
If you want to debug, go to Evaluation -> Debugger, and click on "Break at Messages." Then run your code. Once it gets to the error, you can click "Continue" or look for the highlighted (green) line where the error occurred. You can also hit "Show Stack" to see variable values.