关于asp的ado访问例子

为什么我的用户登陆系统无法连接数据库呢？我

<meta http-equiv=\"Content-Type\" content=\"text/html;charset=gb2312">
<%
if isempty(session("passed")) then
session("passed")=false
end if

if session("passed")=false then
username=request.form("username")
userpwd=request.form("userpwd")

if username="" then
errmsg="请输入用户名和密码"
else

set conn=server.createobject("adodb.connection")
conn.connectionString ="driver={SQL Server};server=(Local);UID=sa;PWD =sa;Database=userman"
conn.open

set rs=server.createobject("adodb.recordset")

set rs.activeconnection=conn

rs.cursortype=3

rs.open"select * from users where username='"&trim(username)&"'"