Hello there Tsubasa,
Hope you're doing well.
It seems that you're trying to access a record from Projects entity and you're passing a null Id (key 0).
So it seems that you're calling an action/function called GetProjects associated to Projects entity, that receives an Id (Identifier), but you're passing it as 0.
You should try to do some debugging to understand why it is happening on your code (most likely, you are not populating this Id variable correctly). Or try to check the usages of that action/function to understand where the problem can be:

It seems to be an Expression inside ScrnTasks screen from MainFlow.
Hope that this helps you!
Kind regards,
Rui Barradas