Access高手请进赐教

大家好，最近做网站遇到一个问题，由于我是新手，实在不知哪出了问题，代码如下：
set rs1=server.createobject("adodb.recordset")
  sql1="select * from user where (id is null)"
rs1.open sql1,secondconn,1,3
rs1.addnew
rs1("username")=username
rs1("password")=password1
rs1("truename")=truename
rs1("companyname")=companyname
rs1("address")=companyaddress
rs1("tel")=companytel
rs1("regtime")=now()
rs1("QuanXian")="guest"
rs1("checked")=false
rs1("logincount")=0
rs1("regip")=request.ServerVariables("REMOTE_ADDR")
rs1("regtime")=now()
rs1("updatetime")=now()
rs1.update
rs1.close
set rs1=nothing
secondconn.close
set secondconn=nothing
response.write "恭喜恭喜，注册成功!"
这段代码无法向数据库里添加记录，数据库连接没有问题，而且我测试过可以从数据库里读数据，请各位庙手赐教