do your store your experiment on the desktop or is it stored in a folder? BTW, do not use spaces in file-names when using such files on different operating systems.
Experiments need to be in their own folder. If your psyexp file is in C:\Users\dimit\Desktop\ then it will try to sync your entire desktop. I would recommend that you put the experiment and resources into a dedicated folder in your documents area.
well, the error message suggests that your experiment is stored on the desktop and not in folder. This is probably the reason for your problem. Spaces in file-names are bad style when working on different operating systems because you do not know how the various operating systems will handle the space in the file-name.
Follow the advice given by wakecarter.
Best wishes Jens