This bug is caused by SP4, where some security API calls are broken.

We have modified SAFileManager's GetFolder.AllowAccess method to take one more optional parameter.

Examples are like:
Suppose domain\guest has no rights on c:\temp1, c:\temp2, c:\temp3, c:\temp4

Set oFM = Server.CreateObject("SoftArtisans.FileManager")

Set oFolder1 = oFM.GetFolder("c:\temp1")
Set oFolder2 = oFM.GetFolder("c:\temp2")
Set oFolder3 = oFM.GetFolder("c:\temp3")
Set oFolder4 = oFM.GetFolder("c:\temp4")

If (Err <> 0) Then

oFolder1.AllowAccess "domain\guest", 126, 1
oFolder2.AllowAccess "domain\guest", 126, 2
oFolder3.AllowAccess "domain\guest", 126, 3
oFolder4.AllowAccess "domain\guest", 126
....

The domain\guest will have rights like:

c:\temp1 File(Full)
c:\temp2 Folder(Full)
c:\temp3 File(Full) Folder(Full)
c:\temp4 File(Full) Folder(Full)

Yes, the last two are the same, i.e. no third parameter or the parameter being 3 change both File and Folder's rights.