I made the changes in the Ethernet library for Arduino 1.0.5 as given on the Wiznet instruction page.
I can ping the WIZ550io from a Linux (Debian) Network tools screen through an ethernet switch (small dedicated network).
When I try to get a Webserver Sketch running on the Uno R3, it compiles and loads. When I send an ethernet address (192.128.1.2) to the Uno from the Linux PC (this is the address that pings from Linux) I get a message saying that “192.168.1.2 refused the connection.”
I’ve got a better idea. Send me Arduino IDE software with the proper Ethernet and SPI libraries installed and I’ll try that. This was supposed to work out of the box. I’m sure you have what I need, one that has been tried and works.
I got this to work satisfactorily, both with the ioShield A and a direct wire connection. Part of the trick seems to be, when you substitute the new Ethernet Library for Wiznet for the standard Arduino R3 library is to copy the new directory over the old one, and choose “copy and replace” (Windows 7) every time that dialog box pops up. I could upload the Arduino IDE I used for others if someone would let me know where that location would be on the Wiznet site.