asp.net 网站运行时错误

很急的问题，在我本机上运行（ASP.NET网站）没有任何问题，放到远程服务器上就出现了如下错误：
Server Error in '/' Application.
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Object reference not set to an instance of an object.
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.

Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.

Source Error:


Line 33:                User user = mu.M_SelectUserByID(id);
Line 34:                this.lblID.Text = id.ToString();
Line 35:                this.lblTel.Text = user.QB_TEL.ToString();
Line 36:                this.lblState.Text = user.QB_STATE.ToString();
Line 37:                this.lblNum.Text = user.QB_NUM.ToString();


Source File: d:\suntek\jxtweb\User\ShowUser.aspx.cs    Line: 35

Stack Trace:


[NullReferenceException: Object reference not set to an instance of an object.]
  User_ShowUser.Page_Load(O