Kevin
Here is the stacktrace
at OakLeaf.MM.Main.Windows.Forms.mmBusinessForm.SetErrorProvider(mmErrorProviderArgs arg)
at OakLeaf.MM.Main.Windows.Forms.mmBusinessForm.DisplayErrorProviderRules(mmBusinessRuleBase bizRule)
at OakLeaf.MM.Main.Windows.Forms.mmBusinessForm.DisplayBrokenRules(mmBusinessRule bizRule)
at OakLeaf.MM.Main.Windows.Forms.mmBusinessForm.PostSaveProcessing(mmBusinessObject bizObj, String tableName, mmSaveDataResult result)
at OakLeaf.MM.Main.Windows.Forms.mmBusinessForm.Save(mmBusinessObject bizObj, String tableName)
at OakLeaf.MM.Main.Windows.Forms.mmBusinessForm.Save(mmBusinessObject bizObj)
at OakLeaf.MM.Main.Windows.Forms.mmBusinessForm.Save()
at NYSTAX.APPDEV.Lockbox.STReg.frmSTRegReturnMaint.MmButton1_Click(Object sender, EventArgs e) in D:\Projects\Lockbox\STReg\STReg\frmSTRegReturnMaint.vb:line 991
at System.Windows.Forms.Control.OnClick(EventArgs e)
at System.Windows.Forms.Button.OnClick(EventArgs e)
at System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent)
at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
at System.Windows.Forms.Control.WndProc(Message& m)
at System.Windows.Forms.ButtonBase.WndProc(Message& m)
at System.Windows.Forms.Button.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 NYSTAX.APPDEV.Lockbox.AppMainEntry.Main() in D:\Projects\Lockbox\Lockbox\Main.vb:line 49

Between this problem and the fact that we dont know if any of our Business Rules are working in parent child senerios (previouse post) we have an entire enterprise level application for tax and finance flat on its back.