Warning: Problem accessing board folder /www/sd

Hi,

I try to get started with the TemperatureWebPage example. I followed the instructions step by step. SD card has a Folder arduino at root and includs the www subfolder. But i allways get the warning after compiling. Selcted port is WiFi to.

Any advise to solve?

I just got this working, what I did.... make sure board is not powered by your computer but by another source.
make sure you can connect to it using the arduino.local web page. Also, make sure you select the IP address of your board
under the ports menu of the arduino software at compile time.