Recursively & Conditionally Move/Loop Through Folder Hierarchy To Fill Array

i am use dir to put into an array all the folders in a folder then enter the first folder and repeat. the problem i am having is when it encounters a file it also puts it into the array and then errors once it trys to enter that "folder" (which is a file)

right now the code doesnt do anything but the plan is then to call another subroutine that lists all the files im looking for in a folder (that sub does work)

what am i doing wrong? all the things i can find on google show it the way i am doing it.

Sub GetDirList(topfolder As String)
Dim FolderArray() As Variant
Dim FolderCount As Integer
Dim FolderName As String

FolderCount = 0
FolderName = Dir(topfolder, vbDirectory)
' Loop until no more folders are found
Do While FolderName <> ""
If Not FolderName = "." Then
If Not FolderName = ".." Then
FolderCount = FolderCount + 1
Redim Preserve FolderArray(1 To FolderCount)
FolderArray(FolderCount) = FolderName
End If
End If