syntax error with Expected:= error

I was pointed in a direction on what I could change in my code that I have been working on but with the changes I am getting 2 different errors. The errors I am receiving are the following, One error is a compile error: syntax error and the other is compile error: Expected:=.

This is the code I am working with right now. The coding in red is my issue I think

Sub PDFPageNumbers()
    Dim FSO As Object
    Dim F_Folder As Object
    Dim F_File As Object
    Dim IterateFolders As String  'I added this in trying to figure the issue out
    Dim Selected_Items As String
    Dim DialogFolder As FileDialog
    Dim Acrobat_File As Acrobat.AcroPDDoc
    Dim i As Long
 
    'Select PDF Directory
    Set DialogFolder = Application.FileDialog(msoFileDialogFolderPicker)
    If DialogFolder.Show = -1 Then
        Selected_Items = DialogFolder.SelectedItems(1)
    Else: Set DialogFolder = Nothing
    End If
    Set DialogFolder = Nothing
    Set FSO = CreateObject("Scripting.FileSystemObject")
    Set F_Folder = FSO.GetFolder(Selected_Items)
         IterateFolders(F_Folder, i)
        i = 2
       Sub IterateFolders(ByVal F_Folder, ByRef i)
        For Each SubFolder In F_Folder
            IterateFolders(SubFolder, i)
    Next
        For Each F_File In F_Folder.Files
            Selected_Items = UCase(F_File.Path)
                If Right(Selected_Items, 4) = ".PDF" Then
                Set Acrobat_File = New Acrobat.AcroPDDoc
                Acrobat_File.Open Selected_Items
                Cells(i, 1).Value = Selected_Items
                Cells(i, 2).Value = Acrobat_File.GetNumPages
                i = i + 1
                Acrobat_File.Close
            Set Acrobat_File = Nothing
        End If
    Next
End Sub
 
    Range("A:B").Columns.AutoFit
 
    Set F_File = Nothing
    Set F_Folder = Nothing
    Set FSO = Nothing
 
End Sub

This is the original code, the code in blue is what I cut out

Sub PDFPageNumbers()
    Dim FSO As Object
    Dim F_Folder As Object
    Dim F_File As Object
    Dim Selected_Items As String
    Dim DialogFolder As FileDialog
    Dim Acrobat_File As Acrobat.AcroPDDoc
    Dim i As Long
 
    'Select PDF Directory
    Set DialogFolder = Application.FileDialog(msoFileDialogFolderPicker)
    If DialogFolder.Show = -1 Then
        Selected_Items = DialogFolder.SelectedItems(1)
    Else: Set DialogFolder = Nothing
    End If
    Set DialogFolder = Nothing
    Set FSO = CreateObject("Scripting.FileSystemObject")
    Set F_Folder = FSO.GetFolder(Selected_Items)
    i = 2
    For Each F_File In F_Folder.Files
        Selected_Items = UCase(F_File.Path)
        If Right(Selected_Items, 4) = ".PDF" Then
            Set Acrobat_File = New Acrobat.AcroPDDoc
            Acrobat_File.Open Selected_Items
            Cells(i, 1).Value = Selected_Items
            Cells(i, 2).Value = Acrobat_File.GetNumPages
            i = i + 1
            Acrobat_File.Close
            Set Acrobat_File = Nothing
        End If
    Next
 
    Range("A:B").Columns.AutoFit
 
    Set F_File = Nothing
    Set F_Folder = Nothing
    Set FSO = Nothing
 
End Sub

This is the code that I pasted in.

  Set F_Folder = FSO.GetFolder(Selected_Items)
    IterateFolders(F_Folder, i)
.....
 
Sub IterateFolders(ByVal F_Folder, ByRef i)
    For Each SubFolder In F_Folder
        IterateFolders(SubFolder, i)
    Next
    For Each F_File In F_Folder.Files
        Selected_Items = UCase(F_File.Path)
        If Right(Selected_Items, 4) = ".PDF" Then
            Set Acrobat_File = New Acrobat.AcroPDDoc
            Acrobat_File.Open Selected_Items
            Cells(i, 1).Value = Selected_Items
            Cells(i, 2).Value = Acrobat_File.GetNumPages
            i = i + 1
            Acrobat_File.Close
            Set Acrobat_File = Nothing
        End If
    Next
End Sub

I don't think IterateFolders is defined. I am confused.

Thanks for the help.

Use parameters without parentheses

Wrong:

IterateFolders(F_Folder, i)

Correct:

IterateFolders F_Folder, i

Ok I change what was suggested and now I am coming up with a different error.

IterateFolders F_Folder, i

Compile error:
Expected Sub, Function, or Property

This is having IterateFolders as a String, but when I change it to an Object the error changes to

Compile error:
Expected End Sub
At this line of code

i = 2

I wish I had a better grasp at VBA.

I have tried looking up other methods and still not getting anywhere. Am I missing something simple?