Hi Jurski,
It looks like permissions were set to read and execute, but not to write. I have updated the permissions to allow write as well. Please try again and let me know if you are able to update now. I am happy to provide FTP access, but have to create a support ticket to do so and so will delay the process a bit. I can also download the files from the server and send you a DropBox link to them so you can take a look. Let me know.
Thanks,
Mike