I got this same error message and fixed it in the easiest way I could. I put my .csv file into a file folder on my desktop, opened desktop in the window next to console on RStudio, and then opened my file there, and checked the box next to my .csv file, then I used the "more" pull down menu at the top of this window to set this as my working directory...probably the easiest thing for SUPER beginners like me :)
