Is your VI acting as a client, or a server? If you're accepting connections on those ports (VI is a server), then you need to use the TCP Listener functions. If your VI is acting as a client, then normally the outgoing port number is selected for you automatically.
It sounds like you're expecting your VI to act as a server, but you're using the TCP Open function, which establishes a connection to a remote machine rather than waiting for an incoming connection, like a client. By setting the VI Server port number in Options, you're telling LabVIEW to act as a server (and accept incoming connections) on that port, but then you have no control over that port - it expects to send VI Server data, and not the data that your code sends. If your VI is going to act as a server, you cannot have VI Server open the ports that you want to use, because you'll get an error - only one application (or in this case, part of an application) can listen on a port at a time.
If I haven't described your problem correctly, please upload your code and the text of the error that occurs.
