一个图片上传程序，我不知道哪里错了

[2321zhf]

formdata=request.binaryread(formsize)
bncrlf=chrB(13) & chrB(10)
divider=leftB(formdata,clng(instrb(formdata,bncrlf))-1)
datastart=instrb(formdata,bncrlf & bncrlf)+4
dataend=instrb(datastart+1,formdata,divider)-datastart
mydata=midb(formdata,datastart,dataend)
..............





<%
Dim SQLStr
SQLStr="Update pic set [index] = 0 Where user_id =" & Session("u_id")
conn.execute (SQLStr)
Set rs = Server.CreateObject("ADODB.Recordset")
rs.Open "pic",conn,3,2
rs.addnew
rs("big").appendchunk mydata
rs("user_id")=session("u_id")
rs("size")=formsize
rs("date")=now()
rs("index")=1
rs.update

set rs=nothing
set conn=nothing
%>

提示错误是：
[Microsoft][ODBC SQL Server Driver][SQL Server]在关键字 'index' 附近有语法错误。