猴子审判的影响:标准表达式中数据类型不匹配。

各位高手请帮我看一下这段代码那里出错了!
<%
' *** Validate request to log in to this site.
MM_LoginAction = Request.ServerVariables("URL")
If Request.QueryString<>"" Then MM_LoginAction = MM_LoginAction + "?" + Server.HTMLEncode(Request.QueryString)
MM_valUsername=CStr(Request.Form("username"))
If MM_valUsername <> "" Then
MM_fldUserAuthorization=""
MM_redirectLoginSuccess="../ZXDY/zxdy-ztlb.asp"
MM_redirectLoginFailed="../ZXDY/zxdy-tw.asp"
MM_flag="ADODB.Recordset"
set MM_rsUser = Server.CreateObject(MM_flag)
MM_rsUser.ActiveConnection = MM_jpkc_STRING
MM_rsUser.Source = "SELECT username, password"
If MM_fldUserAuthorization <> "" Then MM_rsUser.Source = MM_rsUser.Source & "," & MM_fldUserAuthorization
MM_rsUser.Source = MM_rsUser.Source & " FROM admin WHERE username='" & Replace(MM_valUsername,"'","''") &"' AND password='" & Replace(Request.Form("password"),"'","''") & "'"
MM_rsUser.CursorType = 0
MM_rsUser.CursorLocation = 2
MM_rsUser.LockType = 3
MM_rsUser.Open
If Not MM_rsUser.EOF Or Not MM_rsUser.BOF Then
' username and password match - this is a valid user
Session("MM_Username") = MM_valUsername
If (MM_fldUserAuthorization <> "") Then
Session("MM_UserAuthorization") = CStr(MM_rsUser.Fields.Item(MM_fldUserAuthorization).Value)
Else
Session("MM_UserAuthorization") = ""
End If
if CStr(Request.QueryString("accessdenied")) <> "" And false Then
MM_redirectLoginSuccess = Request.QueryString("accessdenied")
End If
MM_rsUser.Close
Response.Redirect(MM_redirectLoginSuccess)
End If
MM_rsUser.Close
Response.Redirect(MM_redirectLoginFailed)
End If
%>
网页提交后显示:
Microsoft OLE DB Provider for ODBC Drivers (0x80040E07)
[Microsoft][ODBC Microsoft Access Driver] 标准表达式中数据类型不匹配。
SQL语句中的参数类型和数据库中定义的表的字段的类型是一致的啊?但就是老是出错,郁闷....