[techhelpbb]

Nope it's not a single versus double quotation issue.

The first thing a browser will send you after you click the button is the following text:
POST / HTTP/1.1

So remember the original code is trying to read what the browser sends and then act on that information. Plus the original code is obsolete.

So if you look for "/" first what will you find?
Now look at what it looks for next...

Remember each time the Atmel AVR MCU takes a character from the ethernet chip's buffer that character is no longer available in the ethernet chip to read again. So if you look for the "/" first. Will you ever find "POST"?