Runtime error 4172 on Save As...

Hi, I installed a macro that allows Word 2007 to remember the last file location opened. The link to the macro was found by one of you wonderful experts here at Experts Exchange: http://forums.mydigitallife.info/threads/21597-Make-Word-2100-remember-the-last-location-it-saved-or-opened-a-document

The macro was written for 2010 and had not yet been tested for 2007.  It does what I wanted it to do, but I've realized now that something in it must be wrong, because the Save As function no longer works, whether I use the keyboard command (F12) or the menu alternative.  It triggers a runtime error 4172.

When I click on Debug, Visual Basic highlights the line: "ChangeFileOpenDirectory MyString" in the next to the last sub:

Function FilePath(iDialog)
    Dim MyString As String
    uProfile = Environ("USERPROFILE")
   
    If FileOrDirExists(uProfile & "\FilePath.txt") Then
        Else: GoTo SkipInput
    End If
   
    Open uProfile & "\FilePath.txt" For Input As #1
    Do While Not EOF(1)
        Line Input #1, MyString
    Loop
    Close #1
   
    ChangeFileOpenDirectory MyString
   
SkipInput:
    If iDialog = "Save" Then
        ActiveDocument.Save
    Else
        Set nDialog = Dialogs(iDialog)
        On Error Resume Next
            With nDialog
                .Show
            End With
        On Error GoTo 0
    End If
           
    Open uProfile & "\FilePath.txt" For Output As #2
        Write #2, CurDir()
    Close #2
   
End Function

I'm afraid VB is greek to me.  Is it obvious to anyone here what's incorrect in the passage?

Many thanks in advance!