请教一个问题，INSERT INTO 语句的语法错误

<%@Language=VBScript%>
<%
Dim Nick,Name1,Password,Email
Dim Province,City,Address,Zip,Phon
Nick=Trim(Request.Form("Nick"))
Name=Trim(Request.Form("Name"))
Password=Trim(Request.Form("Password"))
rePass=Trim(Request.Form("rePass"))
Email=Trim(Request.Form("Email"))
Province=Trim(Request.Form("Province"))
City=Trim(Request.Form("City"))
Address=Trim(Request.Form("Address"))
Zip=Trim(Request.Form("Zip"))
Phon=Trim(Request.Form("Phon"))

If Nick="" OR Name="" OR Password="" OR rePass="" OR Email="" OR Phon="" Then
ShowMessage "有必填项目没有填写！"
Set Conn=Nothing
Else
IF Password<>rePass then
ShowMessage "两次输入的密码不一样！"
set conn=nothing
end if
set conn=server.createobject("ADODB.CONNECTION")
P1="Provider=Microsoft.Jet.OLEDB.4.0;"
Path1="Data Source="&Server.MapPath("Users.mdb")
conn.open P1&Path1
set rs=Server.CreateObject("ADODB.Recordset")
sql="Select *From Users Where Nick="&Nick&""
rs.open sql,conn,0,1
if rs.eof and rs.bof then
sql="insert into Users (Nick,Password,Name,Email,Province,City,Address,Zip,Phon)"&"Values('"&Nick&"','"&Password&"','"&Name&"','"&Email&"','"&Province&"','"&City&"','"&Address&"','"&Zip&"','"&Phon&"')"
Conn.execute sql
rs.close
set rs=nothing
set conn=nothing
response.write"<center>祝贺你注册成功！"&"按<a href=Welcome.asp>这里</a>进入欢迎页面</center>"
else
rs.close
set rs=Nothing
set conn=nothing
ShowMessage "此登录名已被注册！"
end if
end if
%>
<!--显示返回重新填写信息的Sub过程：-->
<%Sub ShowMessage(msg)%>
<body bgcolor="#ccffff">
<center>
<h3><%=msg%></h3>
</center>
<form>
<p align="center">
<input type=Button Value="返回重新填写" OnClick="history.back();">
</p>
</form>
</body>
<% Response.End %>
<% End Sub%>

执行这些语句的老是提示出错，是什么原因呢？
谢谢！

出错提示是：Microsoft JET Database Engine 错误 '80040e14'

INSERT INTO 语句的语法错误。

/qing/Checkregi.asp，行 33