Possibly your Linux's Firewall is on the way. On UbuntuIbex w/ GNOME, I installed Gufw -> set "Defaultly ALLOW traffic" -> "Shutdown Firewall" and LAN started to work BETTER but not perfectly. Sometimes "Enable Firewall" -> "Defaultly DENY traffic" -> add needed ports (see www.portforward.com -> "Router list" -> select "TW-EA-510" as the router and examine what ports it tells you to allow) worked even better.
