Kevin,

I checked and rechecked the binding properties and they are all correct. One piece of information that may be helpful is that when I go to the bindingsourcemember and click on the ellipsis, it does not show either the tables or the fields. The binding source does show the tables. I have a feeling that this may be a FoxPro issue. I did build the same form from scratch, just in case cutting and pasting caused the problem but I got the same result. Here's the stack trace. Thanks, as always, for your help.

   at System.ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument argument, ExceptionResource resource)
   at System.ThrowHelper.ThrowArgumentOutOfRangeException()
   at System.Collections.Generic.List`1.get_Item(Int32 index)
   at OakLeaf.MM.Main.Windows.Forms.mmBindingStrategyBase.RemoveBindingSourceDataTable(Control control, DataTable dt)
   at OakLeaf.MM.Main.Windows.Forms.mmBindingStrategySimple.BindData(ImmBindingSimple mmControl, DataSet ds, String tableName, String fieldName, mmBusinessObject bizObj)
   at OakLeaf.MM.Main.Windows.Forms.mmBindingStrategySimple.BindData(ImmBindingSimple mmControl, mmBusinessObject bizObj, mmBusinessStateChangeEventArgs e)
   at OakLeaf.MM.Main.Windows.Forms.mmBindingStrategySimple.BindData(ImmBindingSimple mmControl, mmBaseBusinessObject bizObj, mmBusinessStateChangeEventArgs e)
   at OakLeaf.MM.Main.Windows.Forms.mmTextBox.OnBindData(mmBaseBusinessObject bindingSource, mmBusinessStateChangeEventArgs e)
   at OakLeaf.MM.Main.Windows.Forms.mmUIHelper.StateChangeHandlerSimple(Control control, mmBaseBusinessObject bizObj, mmBusinessStateChangeEventArgs e)
   at OakLeaf.MM.Main.Windows.Forms.mmTextBox.StateChangeHandler(mmBaseBusinessObject bizObj, mmBusinessStateChangeEventArgs e)
   at OakLeaf.MM.Main.Business.mmBusinessStateChangeDelegate.Invoke(mmBaseBusinessObject bizObj, mmBusinessStateChangeEventArgs e)
   at OakLeaf.MM.Main.Business.mmBusinessObject.OnStateChange(mmBusinessState bizState, String tableName, Object primaryKeyValue, Object[] primaryKeyValues)
   at OakLeaf.MM.Main.Business.mmBusinessObject.CallStateChange(mmBusinessState bizState, String tableName, DataRow dr)
   at OakLeaf.MM.Main.Business.mmBusinessObject.CallStateChange(mmBusinessState bizState, String tableName)
   at OakLeaf.MM.Main.Business.mmBusinessObject.FillDataSet(DataSet ds, String command, String tableName, String databaseKey, CommandType cmdType, IDbDataParameter[] dataParams)
   at OakLeaf.MM.Main.Business.mmBusinessObject.FillDataSet(DataSet ds, String command, String tableName, String databaseKey, IDbDataParameter[] dataParams)
   at OakLeaf.MM.Main.Business.mmBusinessObject.FillDataSet(DataSet ds, String command, String tableName, IDbDataParameter[] dataParams)
   at ESK.DataUploadSystem.Business.Invoice.GetInvoiceByInvoiceNo(String invoiceNo) in C:\deve\ESK Invoice Upload System Business\Invoice.cs:line 138
   at ESK.InvoiceUploadSystem.Windows.ViewInvoices.ddlInvoiceNo_SelectedIndexChanged(Object sender, EventArgs e) in C:\deve\ESK Invoice Upload System Windows\ViewInvoices.cs:line 57
   at System.Windows.Forms.ComboBox.OnSelectedIndexChanged(EventArgs e)
   at System.Windows.Forms.ComboBox.WmReflectCommand(Message& m)
   at System.Windows.Forms.ComboBox.WndProc(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
   at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
   at System.Windows.Forms.UnsafeNativeMethods.SendMessage(HandleRef hWnd, Int32 msg, IntPtr wParam, IntPtr lParam)
   at System.Windows.Forms.Control.SendMessage(Int32 msg, IntPtr wparam, IntPtr lparam)
   at System.Windows.Forms.Control.ReflectMessageInternal(IntPtr hWnd, Message& m)
   at System.Windows.Forms.Control.WmCommand(Message& m)
   at System.Windows.Forms.Control.WndProc(Message& m)
   at System.Windows.Forms.ScrollableControl.WndProc(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
   at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
   at System.Windows.Forms.UnsafeNativeMethods.CallWindowProc(IntPtr wndProc, IntPtr hWnd, Int32 msg, IntPtr wParam, IntPtr lParam)
   at System.Windows.Forms.NativeWindow.DefWndProc(Message& m)
   at System.Windows.Forms.Control.DefWndProc(Message& m)
   at System.Windows.Forms.Control.WmCommand(Message& m)
   at System.Windows.Forms.Control.WndProc(Message& m)
   at System.Windows.Forms.ComboBox.WndProc(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
   at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
   at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg)
   at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(Int32 dwComponentID, Int32 reason, Int32 pvLoopData)
   at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context)
   at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context)
   at System.Windows.Forms.Application.Run(Form mainForm)
   at ESK.InvoiceUploadSystem.Windows.Main.AppMainEntry.Main() in C:\deve\ESK Invoice Upload System Windows\Main.cs:line 45