FORALL alias variable is not of same data type: <name>

You reused a ForAll reference variable, but the array, list, or collection being iterated over is of a different data type than the collection previously iterated over using the same variable. For example:

Dim X(10) As Integer
Dim Y(10) As Long

ForAll I In X
  ' ...
End ForAll

ForAll I In Y     ' Error. I is an Integer before;
                  ' it can't be Long here.
End ForAll

Use a different variable: either an existing ForAll reference variable of the correct type, or a new variable.