moss 2007 自定义NewForm.aspx 注意事项 报错Unable to display this Web Part

我新建了一个Discussion Board，然后修改了NewForm.aspx，将自带的ListForm WebPart删除，添加了Custom List Form，之后Allitems.aspx页面在Sharepoint Designer里显示正常，在浏览器浏览的时候报错，报错信息如下：

Unable to display this Web Part. To troubleshoot the problem, open this Web page in a Windows SharePoint Services-compatible HTML editor such as Microsoft Office SharePoint Designer. If the problem persists, contact your Web server administrator.

后来找了好久的原因，才发现不能将自带的ListForm WebPart删除，只能将其设置隐藏。