Package: (Windows client:) x2goclient-4.0.5.0-2015.07.31-setup.exe;  (Ubuntu server:) x2goserver_4.0.1.19-0~1064~ubuntu14.04.1
Version: see above

On Windows client, if file shareing directory is set under "C:\Users\%USER%\", then it can be accessed on Linux server.
However, if file sharing directory on Windows client is set out of the above scope (e.g. "C:\foobar"), then it can't be accessed on Linux server due to lack of r/w permission.

For Example:
A) File sharing on Windows is set to "C:\Users\ayuanx\Test", notice the permission is "drwx".

$ ll ~/media/disk/                            
total 8.0K
drwx------ 3 ayuanx ayuanx 4.0K Sep 15 11:27 ./
drwx------ 5 ayuanx ayuanx 4.0K Sep 15 11:27 ../
drwx------ 1 ayuanx ayuanx    0 Sep 15 11:28 _cygdrive_C_Users_ayuanx_Test/

$ ll ~/media/disk/_cygdrive_C_Users_ayuanx_Test/
total 4.0K
drwx------ 1 ayuanx ayuanx    0 Sep 15 11:28 ./
drwx------ 3 ayuanx ayuanx 4.0K Sep 15 11:27 ../
-rwx------ 1 ayuanx ayuanx    0 Sep 15 10:45 New Text Document.txt*

$ touch write_test.txt; ll
total 4.0K
drwx------ 1 ayuanx ayuanx    0 Sep 15 11:59 ./
drwx------ 3 ayuanx ayuanx 4.0K Sep 15 11:27 ../
-rwx------ 1 ayuanx ayuanx    0 Sep 15 10:45 New Text Document.txt*
-rw-r--r-- 1 ayuanx ayuanx    0 Sep 15 11:59 write_test.txt


B) File sharing on Windows is set to "C:\Temp", notice the permission is "d", not accessible at all.

$ ll ~/media/disk/
total 8.0K
drwx------ 3 ayuanx ayuanx 4.0K Sep 15 10:46 ./
drwx------ 5 ayuanx ayuanx 4.0K Sep 15 10:46 ../
d--------- 1 ayuanx ayuanx    0 Sep 15 10:45 _cygdrive_C_Temp/

$ cd ~/media/disk/_cygdrive_C_Temp/
bash: cd: /home/ayuanx/media/disk/_cygdrive_C_Temp/: Permission denied