以上为图片：
以下为报错的详细内容：
注：这是一个办公软件 只有个别的电脑安装oa系统后,点击邮箱的功能才报此错。
请有解决过类似或者此问题的大佬请帮忙看看，谢谢。
************** Exception Text **************
: Object reference not set to an instance of an object.
at ()
at ()
at ..ctor()
at .()
at ..ctor()
at .()
at ..ctor()
at .(Object , NavBarLinkEventArgs )
at (Object linkEvent, NavBarItemLink link)
at (NavBarItemLink link)
at (NavBarItemLink link)
at (NavBarItemLink link)
at (NavBarHitInfo hitInfo)
at (NavBarHitInfo hitInfo)
at (MouseEventArgs e)
at (MouseEventArgs ev)
at (Message& m, MouseButtons button, Int32 clicks)
at (Message& m)
at (Message& m)
at (Message& m)
at (Message& m)
at (IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)