SQL server not found error

I'm very new to ASP but I'm trying to set up a login for my client to enable their customers to book reservations online. Someone else wrote the code for me, another guy again is looking after their database (since it's 600 miles away from where I am) and I'm just the one trying to make it all work! Any help you can give me would be greatly appreciated!!

The guy looking after their server says he's opened a port for me and rewritten the firewall rules to allow access by my server but this is the error message I'm getting when I try to log on:

[Microsoft][ODBC SQL Server Driver][Named Pipes]Specified SQL server not found.-2147467259

ADODB.Recordset error '800a0e7d'

Operation is not allowed on an object referencing a closed or invalid connection.

The code that refers to opening the data connection looks like this...

Sub LiveryLogin(username,password)
     Set rs = Server.CreateObject("ADODB.Recordset")
     sql= "SELECT CustomerID,Agent,First_Name,Last_Name,Company FROM customer Where username = '"&UserName&"' and Password='"&Password&"'"
     rs.Open sql, oConn,0,1

I'm using a valid username and password and I've named the database that we're trying to access elsewhere in the routines. I'm sorry but servers and ASP are not my forte... I don't even know which bits of information are relevant to give you to help you answer my question.

I don't know what a DSN is, and no, I can't access the SQL server other than through this login routine from their web page.

I program in HTML and Javascript primarily but my client bought this ASP reservation system from a third party and has left it up to me to install it.    The company that sold the system to them has no concept of customer support whatsoever so they've been very little help, if any. Usually when I build my sites I just FTP them up to whatever server they're going to be hosted on and everything works fine. In this case, they've had someone else set up their back office system for them and what I'm installing is just the interface that allows their clients to make their reservations online through their existing website.

When my client's tech guy emailed me to say that he had opened the port, he said:

The port is open as described below.

ISA-Created packet filter
"secure.clientsdomain.com"
TCP
BOTH
PORT 9600

???????

Also, has SQL been installed on prot 9600? If yes, you need to put that into your connection string as it would default to 1433 otherwise.