Hi Gustavo,

The screenshot of the script shared by you has a variable named 'grInc' whereas the error is related to the variable 'gr'. So, the error you are getting is not related the script you shared. Try to find out if there is any other onChange script running on the same field or another way to debug is to check if there is any onChange script which is creating a error message on this specific field.

Regards,

Ritesh