SSIS Error: Error: ForEach Variable Mapping number n to variable "User:: n1 " cannot be applied.

The exact error I got was
Error: ForEach Variable Mapping number 2 to variable "User::i_HospitalCode" cannot be applied.
I spent almost 2 hours trying to find out what the problem was. It was the problem in the data type. I was declaring the data type of  variable User::i_HospitalCode as string where as the resultset ( returned by the stored procedure) was integer.
I changed the data type of the variable  User::i_HospitalCode  in the variable declaration window and it worked!