I had a need to create folders from Access, but needed a means to first validate that the folders names were acceptable as Windows does not allow certain characters and has certain basic rules (refer to the 2 links commented out in the function below for all the details).  As such, I created the following simple function which I supply the folder name to and it returns True/False whether the string is acceptable or not.  It really wasn’t very difficult and this is the perfect situation in which to utilize the power of regular expression to validate the folder name with!

'---------------------------------------------------------------------------------------
' Procedure : IsInvalidFolderName
' Author    : Daniel Pineault, CARDA Consultants Inc.
' Website   : http://www.cardaconsultants.com
' Purpose   : Validates whether the string passed is an acceptable folder name
' Copyright : The following may be altered and reused as you wish so long as the
'             copyright notice is left unchanged (including Author, Website and
'             Copyright).  It may not be sold/resold or reposted on other sites (links
'             back to this site are allowed).
'
' Input Variables:
' ~~~~~~~~~~~~~~~~
' sFolderName name of the folder you're wanting to create
'
' Usage:
' ~~~~~~
' IsValidFolderName("MsAccess Databases") will return True
' IsValidFolderName("MsAccess :: Databases") will return False
'
' Revision History:
' Rev       Date(yyyy/mm/dd)        Description
' **************************************************************************************
' 1         2012-Feb-01                 Initial Release
'---------------------------------------------------------------------------------------
Function IsValidFolderName(ByVal sFolderName As String) As Boolean
'http://msdn.microsoft.com/en-us/library/windows/desktop/aa365247(v=vs.85).aspx#file_and_directory_names
'http://msdn.microsoft.com/en-us/library/ie/ms974570.aspx
    On Error GoTo Error_Handler
    Dim oRegEx          As Object

    'Check to see if any illegal characters have been used
    Set oRegEx = CreateObject("vbscript.regexp")
    oRegEx.Pattern = "[<>:""/\\\|\?\*]"
    IsValidFolderName = Not oRegEx.test(sFolderName)
    'Ensure the folder name does end with a . or a blank space
    If Right(sFolderName, 1) = "." Then IsValidFolderName = False
    If Right(sFolderName, 1) = " " Then IsValidFolderName = False

Error_Handler_Exit:
    On Error Resume Next
    Set oRegEx = Nothing
    Exit Function

Error_Handler:
    MsgBox "The following error has occurred" & vbCrLf & vbCrLf & _
           "Error Number: " & Err.Number & vbCrLf & vbCrLf & _
           "Error Source: IsInvalidFolderName" & vbCrLf & _
           "Error Description: " & Err.Description, _
           vbCritical, "An Error has Occurred!"
    Resume Error_Handler_Exit
End Function

Enjoy!