prepared statement for MySql database

Hello,
Are there exist prepared statements for MySql databases that can be used through ASP. I have this code

        Dim conn
	
	Set conn = Server.CreateObject("ADODB.Connection")
	conn.Open "DRIVER={MySQL ODBC 3.51 Driver}; SERVER=server_name; Port=3306; DATABASE=db_name; UID=un;PASSWORD=pwd; OPTION=4"
        Dim rs
        Dim dbCommand
	Set dbCommand = Server.CreateObject("ADODB.Command")
	Set dbCommand.ActiveConnection = conn
	dbCommand.CommandType = adCmdText
	dbCommand.CommandText = "SELECT username, password, autcode FROM users WHERE username=? AND password=?"
	dbCommand.Parameters.Append (dbCommand.CreateParameter("username", adChar, adParamInput, Len(username), username))
	dbCommand.Parameters.Append (dbCommand.CreateParameter("password", adChar, adParamInput, Len(password), password))
	Set rs = dbCommand.Execute

Code (markup):

but at line

dbCommand.CommandType = adCmdText

Code (markup):

I am getting error mesage:
"ADODB.Command error '800a0bb9'

Arguments are of the wrong type, are out of acceptable range, or are in conflict with one another. "

Can someone help me? Thank you in advance.

 

Did you set value to adCmdText?