I'm not certain about VB but in C# the parameters are passed in by reference. Also, for SqlString you have to refer to them as follows:

sqlparam(0).Value = User_UserName.Value; // the value of the SqlString

sqlparam(1).Value = User_Password.Value;

sqlparam(2).Value = Station.Value; // the value of the SqlString

sqlparam(3).Value = Users_RowID

sqlparam(4).Value = Users_Name.Value; // the value of the SqlString

sqlparam(5).Value = Success

sqlparam(6).Value = Default_Message.Value; // the value of the SqlString