Check if dir exists the create dir using field from form

[Zepher2]

I have very limited knowledge of vba. I amtrying to check and see if a sub-folder exists on my c drive and if it does not then create one using the variable name FileNo.

The first time I run the procedure it creates the file as it should. However, if I click the button again I get this error message. run time error 75 "path\file access error.

Her is the code I am using. What am I doing wrong?

Thanks in advance

Private Sub CmdMakeDir_Click()

Dim test As Integer

test = Len(Dir("C:\Client Data" & "\" & Me.[FileNo]))
If test = 0 Then
'' directory doesn't exist

MkDir "C:\Client Data" & "\" & Me.[FileNo]

End If
End Sub