Anyone familiar with this API call?

Declare Function WNetAddConnection2 Lib "mpr.dll" Alias "WNetAddConnection2A" (lpNetResource As NETRESOURCE, ByVal lpPassword As String, ByVal lpUserName As String, ByVal dwFlags As Long) As Long

Every time I specify username and password, I got an error 1219 - but if dont supply those credentials, it works fine.

Can someone sets some lights on this question?

I also ran into another issue that if a drive is already mapped, my vb exe maps another drive. Say I is mapped, so map J. But when I want to disconnect the drive, I didn't want to disconnect I because it wasn't mapped by my exe. How can I achieve that?