Check If Directory Exists Before Save

I am looking to see if a directory exists, and if it does, to save a file in it, otherwise create it, then save the file. My IsFileThere function works fine on files, but does not detect directories. The len(Dir(Filename)) statement always returns a 0, with the Dir statement always simply populating with "". It works fine on filenames - so can anyone tell me why it does not pick up directories?
Shouldn't the Dir function on a directory name return "."? I have excerpted some of my code to include here: Global Const StoredJobsSubdirectory = "Jobs"

Dim AppPath As String: AppPath = ActiveWorkbook.Path
'other code in here - activeworkbook changed, hence previous line
If IsFileThere(AppPath & "" & StoredJobsSubdirectory) Then
ActiveWorkbook.SaveAs FileName:=AppPath & "" & StoredJobsSubdirectory & _
"" & NameString & ".xls"
Else
MkDir AppPath & "" & StoredJobsSubdirectory
ActiveWorkbook.SaveAs FileName:=AppPath & "" & StoredJobsSubdirectory & _
"" & NameString & ".xls"
End If............................