Hi!<BR><BR>I have finished a asp.net application (it has been developed in Windows XP Professional & IIS 5.0) and now i am trying to put it in another Web Server (W2k Server & IIS 5.0) but i am having some trouble in doing so.<BR><BR>I windows XP it all works fine, but when i pass it all to W2k, i get an error:<BR><BR>-----------------------------------------------------<BR><BR>Server Error in &#039;/mac&#039; Application.<BR>--------------------------------------------------------------------------------<BR><BR>Object reference not set to an instance of an object. <BR>Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. <BR><BR>Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.<BR><BR>Source Error: <BR><BR><BR>Line 62: ds = _macDBUser.AuthenticateUser(TextBox1.Text, TextBox2.Text);<BR>Line 63: <BR>Line 64: intIsAuthentic = ds.Tables["t_utilizador"].Rows.Count;<BR>Line 65: <BR>Line 66: if (intIsAuthentic &#060; 1)<BR> <BR><BR>Source File: c:websintranetmacdefault.aspx.cs Line: 64 <BR><BR>Stack Trace: <BR><BR><BR>[NullReferenceException: Object reference not set to an instance of an object.]<BR> avaltaxo.WebForm1.Button1_Click(Object sender, EventArgs e) in c:websintranetmacdefault.aspx.cs:64<BR> System.Web.UI.WebControls.Button.OnClick(EventArgs e) +108<BR> System.Web.UI.WebControls.Button.System.Web.UI.IPo stBackEventHandler.RaisePostBackEvent(String eventArgument) +57<BR> System.Web.UI.Page.RaisePostBackEvent(IPostBackEve ntHandler sourceControl, String eventArgument) +18<BR> System.Web.UI.Page.RaisePostBackEvent(NameValueCol lection postData) +33<BR> System.Web.UI.Page.ProcessRequestMain() +1263<BR><BR> <BR>-------------------------------------------------------------<BR><BR>and the function that is causing the error:<BR><BR>-------------------------------------------------------------<BR><BR>public DataSet AuthenticateAdmin(string Login, string Password)<BR>{<BR> string strSql;<BR> strSql = "SELECT t_utilizador.IDUtilizador, t_utilizador.Nome, t_utilizador.Apelido, t_grupo.IDGrupo, t_grupo.Nome " + <BR>"FROM t_utilizador INNER JOIN (t_grupo INNER JOIN t_utilizador_grupo ON t_grupo.IDGrupo = " +<BR>"t_utilizador_grupo.IDGrupo) ON t_utilizador.IDUtilizador = t_utilizador_grupo.IDUtilizador " +<BR>" WHERE (((t_grupo.Nome)=&#039;administrador&#039; AND (t_utilizador.Login)= &#039;" + Login + "&#039; AND (t_utilizador.PassUtilizador) = &#039;" + Password + "&#039;))";<BR><BR> OdbcCommand cmd = new OdbcCommand( strSql, OdbcConn);<BR> OdbcDataAdapter da = new OdbcDataAdapter(cmd);<BR> DataSet ds = new DataSet(); <BR> try<BR> {<BR> da.Fill(ds, "t_utilizador");<BR> return ds;<BR> }<BR> catch (Exception ex)<BR> {<BR> return ds;<BR> }<BR>}<BR><BR>--------------------------------------------------------<BR><BR>and after debugging, i can see that in W2k, the DataSet (ds) is not getting any value from the database (Access 2000).<BR><BR>I am using the odbc driver delivered from microsoft to ASP.NET.<BR><BR>I really don&#039;t know what is happening here, because in XP all is working fine!<BR><BR>If anyone could help!!!<BR><BR>