7.3兽王猎人做任务:字段 'NEWS.Content' 不能是零长度的字符串。

ewebeditor 编辑器提交数据到数据库时
说字段 'NEWS.Content' 不能是零长度的字符串。
我news. content 字段类型为备注
允许为空值 请问是什么原因？？
这段是上传数据代码
<!--#include file="conn.asp"-->
<!--#include file="admin.asp"-->
<!-- #include file="Inc/Head.asp" -->
<%
title=request("title")
BigClassName=request("BigClassName")
SmallClassName=request("SmallClassName")

mContent = trim(Request.form("cnWords"))
mContent = Replace(mContent,"<script","<sscript")
mContent = Replace(mContent,"/script>","/scripts>")
mContent = Replace(mContent,"/script >","/scripts>")
mimageNum = Request.form("imageNum")

firstImageName = trim(Request.form("editFirstImageName"))
user=request("user")

set rs=server.createobject("adodb.recordset")
sql="select * from NEWS where (id is null)"
rs.open sql,conn,1,3
rs.addnew
rs("title")=title
rs("content")=mcontent
rs("user")=user
rs("BigClassName")=BigClassName
rs("SmallClassName")=SmallClassName
if mimageNum<>"" then rs("imageNum") = mimageNum
if firstImageName<>"" then rs("firstImageName") = firstImageName
rs.update
rs.close
set rs=nothing
conn.close
set conn=nothing
response.write "<script language='javascript'>" & chr(13)
response.write "alert('新闻提交成功！');" & Chr(13)
response.write "window.document.location.href='News_Manage.asp';"&Chr(13)
response.write "</script>" & Chr(13)
Response.End
%>