Operation add lists cannot accept: Empty [...] Cant find the problem!

Hi guys, Im fairly new to app inventor 2 and we have to make a school diary app. Im currently making the 'Assignment' Page, but I've encountered a problem. Everytime I press Submit, I am faced with 

The operation add items to list cannot accept the arguments: Empty Religion
Note: You will not see another error reported for 5 seconds.

(Religion is the subject in this case)

I have asked my teacher and solved it, but I don't what I have done that the error appears again. Please help! Thanks!

Assignment.aia

Assignment.apk

most probably you did not initialize your list variable with the create empty list block

It would really help if you provided a screenshot of your relevant blocks, so we can see what you are trying to do, and where the problem may be.