【单据转换】字段映射设置报错

BOS自定义单据《销售费用报支单》，配置生成出纳付款单的单据转换规则，在设置字段映射时系统提示报错：

发生时间： 2014年10月21日 18:42:09
错误来源： Kingdee.BOS.DomainModelDesigner
错误信息： Object reference not set to an instance of an object.
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调用堆栈：
at Kingdee.BOS.DomainModelDesigner.ConvertEditors.frmBillFieldSelect.tvField_FocusedNodeChanged(Object sender, FocusedNodeChangedEventArgs e)
at DevExpress.XtraTreeList.TreeList.InternalSetFocusedRowIndex(Int32 newFocusedRowIndex)
at DevExpress.XtraTreeList.TreeList.SetFocusedNode(TreeListNode node)
at Kingdee.BOS.DomainModelDesigner.ConvertEditors.frmBillFieldSelect.SetSelectedNode()
at Kingdee.BOS.DomainModelDesigner.ConvertEditors.frmBillFieldSelect.InitFieldTree()
at System.Windows.Forms.Form.SetVisibleCore(Boolean value)
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.Form.ShowDialog(IWin32Window owner)
at Kingdee.BOS.DomainModelDesigner.ConvertEditors.frmDefaultPolicyEditor.ibtnSourceField_ButtonClick(Object sender, ButtonPressedEventArgs e)
at DevExpress.XtraEditors.ButtonEdit.OnMouseUp(MouseEventArgs e)
at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
at System.Windows.Forms.Control.WndProc(Message& m)
at DevExpress.Utils.Controls.ControlBase.WndProc(Message& m)
at DevExpress.XtraEditors.BaseControl.WndProc(Message& msg)
at DevExpress.XtraEditors.TextEdit.WndProc(Message& msg)
at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
错误数据： System.Collections.ListDictionaryInternal