what ftp server on ps3 do u use?
i prefer Blackbox (1.2)
connect LAN cable to pc
start Blackbox
if u get a IP evrything is right

if not check your settings
PC
IP-Adresse:
168.9.0.101
Subnetzmaske:
255.255.255.0
PS3
IP-Adresse:
168.9.0.102
Subnetzmaske:
255.255.255.0
Standard-Router:
168.9.0.101
Prim. DNS:
168.9.0.101
should work
Start Filezilla and connect to 168.9.0.102