When transferring the websites and all related files via FTP it may sometimes happen that not all files are transferred to the web space correctly.
The most common cause for this are the file names containing special characters like "ä", "ö", "ü" or "ß". Quite often whitespace has been accidentally used in the filename, which is not allowed. Plase replace whitespace with the underscore "_" for instance.
After you have checked the file names start the transfer via FTP once again and check if all data have been transferred.