I have a problem with airport connectivity. I have a 500GB Time Capsule, an imac and a g4 laptop, working wirelessly with the time capsule. The laptop has no problems, but the imac has slow-downs in throughput and sporadic signal loss. Sometimes very slow internet connectivity. When using ftp the ftp program gives me prompts: "Could not retrieve file listing" "Couldn't establish data connection" It's weird because in the airport configuration program everything seems to work fine and there is no problem. I must say I remember a while ago I changed some settings in preferences, but I can't remember what exactly, and I tried everything, also settings in my firewall. Any ideas?