I use Toad for Data Analysts at work. At times, for any query you execute, this is the standard answer from toad:
Object reference not set to an instance of an object.
In layman terms, what this means is it does not have a place to output your sql execution. Do the below:
Right click on the window area.
Select “Show Script Results”
Re-execute and see the results.
Have a good day and keep rocking!!