Try to open link in your browser:
http://arduino.arigato.cz/testfile.txt

If success, download sketch:
http://arduino.arigato.cz/http_client_test_vXXX.ino
and run on your Arduino.

Sketch is working on my hardware. I use the following hardware:
http://www.freetronics.com/products/ethermega-arduino-mega-2560-compatible-with-onboard-ethernet
http://www.google.cz/search?q=Hiduino+2560+R3+Womarts
http://www.google.cz/search?q=Funduino+2560+R3
http://www.google.cz/search?q=Ethernet+Shield+R3+W5100+enhanced