Framework .NET - Problema Frameworrk 2.0

Estimados, tengo un servidor donde se alojan aplicaciones con frame 1.1 y solo 1 aplicaicon con 2.0

Desde mi menu que esta en version frame 1.1 doy click a una pagina desde un sitio que esta con frame 2.0

y al leer de la base de datos cuyo procedimiento esta correcto y tratar de pasara el table(0)
me dice que , como prodre solucionar corro este comando en mi servirdor ??


Server Error in '/wISTransaccion' 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 241: Dim clsM As New DAL.maestra.clsM
Line 242: Dim sessionuser As Integer = Session("urlid")
Line 243: Dim dtP As DataTable = clsM.select_multiplestabla(17, 0, "").Tables(0)
Line 244: Dim dtU As DataTable = clsM.select_multiplestabla(18, sessionuser, "").Tables(0)
Line 245: Session("brlColl") = New COLECCIONES.Collection.Collection(dtP, dtU)


Source File: D:WebwISTransaccionUITransaccionNuevowfAlmNuevo.aspx.vb Line: 243

Stack Trace:

[NullReferenceException: Object reference not set to an instance of an object.]
UI_Transaccion_Nuevo_wfAlmNuevo.para_coleccion() in D:WebwISTransaccionUITransaccionNuevowfAlmNuevo.aspx.vb:243
UI_Transaccion_Nuevo_wfAlmNuevo.Page_Load(Object sender, EventArgs e) in D:WebwISTransaccionUITransaccionNuevowfAlmNuevo.aspx.vb:58
System.Web.UI.Control.OnLoad(EventArgs e) +99
System.Web.UI.Control.LoadRecursive() +47
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1436



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Version Information: Microsoft .NET Framework Version:2.0.50727.1433; ASP.NET Version:2.0.50727.1433

GRACIAS

Coloque el código que genera el error try codig catch e AS NullReferenceException end try