silly error in .addnew and .update

[SmagO]

anyone able to help here...is this correct?

set rs = server.CreateObject("ADODB.recordset")
rs.Open "event", conn, 3, 3
rs.AddNew
rs("primarykey") = npk
rs("eventNam") = Request.Form("cEventName")
rs.Update
rs.Close 

i get the following error

Error Type:
Microsoft OLE DB Provider for ODBC Drivers (0x80040E2F)
[Microsoft][ODBC Microsoft Access Driver]Error in row
/admin/adminevent.asp, line 145