I'm very new to Arduino, so please forgive my ignorance. But, I have been looking all night for the answer to this question.
I just received my Arduino Ethernet Shield SD and I was able to give it a MAC and IP and I can ping it. However, when I want to make a slight change to my code, I am unable to upload to the Arduino with my Ethernet Shield attached. Is this normal?
No this is not normal. Sorry I don't have an idea of what is causing it though.
You might try pushing RESET on the shield before trying the upload??
Can you upload with the Ethernet shield attached the blink sketch?
Also, which Arduino are you using?