Error On User Input Script

Error On User Input Script

I'm having this error, could someone helpme with this?
Thanks

Error details:
Error occured while executing on user input script.
Unable to update variable Address
r.Address is null
r is null

This is the Script associated




 r  =  Store  [Store == input.Store];                                                  
input.Address = r.Address;









 input.City = r.City;