Code Executes In Windows 2000 But Not XP PRO

I obtained this code from the Net and am successfully using it on a form in MS ACCESS 2002 under Windows 2000. However, all of the string functions result in compile errors and force debug mode when the form is executed under XP Pro (Compile error: Can't find project or library). Any assistance will be appreciated as I am approaching my deadline for rolling this app out on XP Pro systems. Thanks.

Private Declare Function apiGetUserName Lib "advapi32.dll" Alias "GetUserNameA" (ByVal lpBuffer As String, nSize As Long) As Long
'-----------------------------------------------------------------------------------------
' This code is used to retrieve the network user name by accessing the API apiGetUserName.
' Created by: Unknown (Found on Dev Ashish web site http://home.att.net/~dashish/api)
' This code has not been altered in anyway.
' Added to database: 27 Dec 1999
' Added by: Richard Rensel
'-----------------------------------------------------------------------------------------
Function fOSUserName() As String
On Error GoTo fOSUserName_Err

Dim lngLen As Long, lngX As Long
Dim strUserName As String

strUserName = String$(254, 0)
lngLen = 255
lngX = apiGetUserName(strUserName, lngLen)

If lngX <> 0 Then
fOSUserName = Left$(strUserName, lngLen - 1)
Else
fOSUserName = ""
End If


fOSUserName_Exit: