Employee ID reflected in created by column instead of display name

[Iron]

I wrote a program to import data from excel sheet to sharepoint 2007 list. Around 11000 data gets imported. I have used the below code. My query is I wanted to put "employee's display name" in "created by" column. And im providing the same in excel sheet n in the code. But after the data gets imported I see that few employees data has reflected the created by column with their names. But for few it reflects EMPID only or EMPID + name. I debug the code It takes the right string to display but i did not understand y it gives such results. Also i am running the prog on my machine n not the server, so is it bcoz of this. As I am using test server and then only will deploy to production.Code:\[code\]protected void btnImport_Click(object sender, EventArgs e) { using (SPSite site = new SPSite("URL")) { using (SPWeb web = site.OpenWeb()) { webapp = web.Site.WebApplication; webapp.FormDigestSettings.Enabled = false; SPList list = web.Lists["List name"]; string connString = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=D:\\Test.xlsx;Extended Properties=Excel 12.0"; OleDbConnection oledbConn = new OleDbConnection(connString); oledbConn.Open(); OleDbCommand cmd = new OleDbCommand("SELECT * FROM [Sheet1$]", oledbConn);//contents from sheet1 is selected OleDbDataAdapter oleda = new OleDbDataAdapter(); oleda.SelectCommand = cmd; DataSet ds = new DataSet(); oleda.Fill(ds, "Employees"); DataTable dt = ds.Tables["Employees"]; DataView dv = new DataView(dt); SPSecurity.RunWithElevatedPrivileges(delegate() { using (SPSite elevatedSite = new SPSite("URL")) { elevatedRootWeb = elevatedSite.OpenWeb(); } }); foreach (DataRowView drv in dv) { EMPID = drv["Emp id"].ToString(); DispName = drv["Name"].ToString(); Title = drv["Title"].ToString(); getid = new SPQuery(); getid.Query = "<Where><Eq><FieldRef Name=