连接数据库的问题，测试时提示HTTP 500： 服务器尝试执行请求时遇到了意外情况

<%
str =request.form("xh")
yuwen=request.form("yuwen")
shuxue=request.form("shuxue")
yingyu=request.form("yingyu")
set conn=server.CreateObject("adodb.connection")
conn.open "provider=microsoft.jet.oledb.4.0;data source="& server.MapPath("person.mdb")
set cmd=server.CreateObject(")
cmd.activeconnection = conn
sql="update grade set 数学="&shuxue&",语文="&yuwen&",英语="&yingyu&" where 学号=" & str
response.write(sql)
= sql
cmd.execute
response.Redirect("test.asp")
%>