DataTable Retrieves another DataTable Information? - asp.net

Question

I Have an Exception in my Live Application..DataTable Retrives another DataTable information..
if (HttpContext.Current.User != null)
{
if (Session["username"] != null)
{
string pageName = Page.Page.AppRelativeVirtualPath.Substring(Page.Page.AppRelativeVirtualPath.LastIndexOf('/') + 1);
DataTable dtFeatures2 = new DataTable();
dtFeatures2.Clear();
objMatermenuPL.usertype = Session["UserType"].ToString();
dtFeatures2 = objMastermenuBAL.GetMastermenu(objMatermenuPL);
DataView dt = new DataView(dtFeatures2);
dt.Sort = "fld_feature ASC";
if (dtFeatures2 != null)
{
foreach (Control control in leftpanel.Controls)
{
Type ty = control.GetType();
if (ty.Name.ToUpper() == "HTMLANCHOR")
{
int i = dt.Find(control.ID.Substring(3));
if (i < 0 && control.ID.Contains("lnk"))
control.Visible = false;
if (control.ID.Contains("lnk") && control.ID.Substring(3) + ".aspx" == pageName)
{
HtmlAnchor a = (HtmlAnchor)control;
a.Attributes.Add("class", "active");
}
}
}
}
}
}
else
{
Response.Redirect("~/Login.aspx");
}
This code we use All most all master pages...If an exception Raise,then it comes directly
this line..
dtFeatures2 = objMastermenuBAL.GetMastermenu(objMatermenuPL);
Message like : Cannot find column fld_feature.
"dtFeatures2" is Filled With Before Opened Page DataTable Information...
This exception gone after some..It's Working Fine 100%....Some times only shows these exception...What happend Here........