It may have a different name within the API. Within a declare function of an API, you see
Code:
Declare Function GetDiskFreeSpace Lib "kernel32"
Alias "GetDiskFreeSpaceA"
Code:
(ByVal lpRootPathName As String, lpSectorsPerCluster As Long, lpBytesPerSector As Long, lpNumberOfFreeClusters As Long, lpTtoalNumberOfClusters As Long) As Long
The bold section represents the name of the function within the library that you are using. Maybe that name is different with 2k allowing the user to use the older or newer dialogs.
Also, please let me know if it is, I would like to know.