are you sure you have the right local IP? and port 21? Use Filezilla if you aren't already. You do have the FTP app installed and running on the PS3 correct? There's no reason why you can't connect to it if you are doing all the previous suggestions.
I can't even get this to run. I get this error: "An error occurred during the start operation. (80029519)"
It was asked before but I don't think it was ever answered. Its not anything on Filezillas end because the PS3 ftp server has to be started for Filezilla to be of use in the first place. I have an iphone 3g with 3.1.2 firmware. JB with PSgroove. In fact, the backup loader gives this same error. I assumed I jailbroken the ps3 correctly because if I hadn't, I wouldn't be able to install .pkgs in the first place.