I have a SQL server 2000 instance running on my database server and I want to connect to this instance from my application server where I have setup an alias for this server.My application connects to database using this alias.

My problem here is that my application is not able to connect to the database though I am able to connect to database server using this alias if I do via enterprise manager(But I have to say yes to a message "//ServerName is not known to be running.Do you like to connect? " and after saying Yes, I am able to connect.)
Port I am using is 1433,default one.
We have also setup an alias for the server as well which is same as SQL server alias.

Could anybody suggest me what I should do to connect directly to SQL server using alias(without getting that mesage,where I have to say yes)?