TRY EASIEST METHOD
hi, i also faced the same problem right before my presentation day.
I tried everything I could from the google but it turns out that the problem is the way I manage my file location. You may want to put your css files or js files in any special folder but DW might be unable to access them although you are trying to open a php file, related to the css/js. I tried to move everything into the main folder and voila it works like charm. I hope this would help you guys.