I usually use wireless on my laptop (obviously haha), but my friend saw me using the FTP server at 1mb/s and told me to plug in the wired internet for it to be a load faster. So I did, and I can't figure out how exactly to connect to it... I have Verizon Fios, if that helps any.
Depending on the security settings you might have to configure the connection accordingly. I assume your laptop at least recognises that there is a possible connection? Any security settings should be exactly the same as when you configured it for your wireless.
However, if you're still connected to the same source via wireless that could be the issue. Your laptop most likely has the wireless as the default connection setting. If you go into control panel > Network and Sharing Centre (Windows7) then you can try disabling the wireless so it's forced to use the wired connection. If you then get nothing after that though, just re-enable it.
Are you talking about FTP server for the PS3 backups? If you are, then all you have to do is connect the PS3 and laptop directly via the ethernet ports. Check the IP address of the PS3 from the network connection status. I use FileZilla to connect to the server app. Use the PS3 IP address with port 21, leaving username and password blank. That should do it. You see between 10-20MB/s transfer rate.