Pearson Form Positioner with Locked Workbook

I'm using the pearson form positioner, but I am getting errors with my locked workbook.

ActiveWorkbook.Unprotect propass
Dim PS As Positions
PS = PositionForm(Activities, Range("Y17"), 8, -3, cstFhpFormLeftCellRight, cstFvpFormTopCellTop)
ActiveWorkbook.Protect propass

It is erroring on the line with PS

The error is

Run-time error '1004':
Unable to set the visible property of the Worksheet class

I'm unlocking before and after PS. Do I even unlocked within the PositionForm Function, and it still gives that error? Is there somewhere else in this class I need to unlock?