1) When you publish using FTP, please make sure your Site Path matches your actual site folder.
Ex: if your URL is http://www.abc.com and the root folder is 'abc'. Then your Publishing Info should have 'abc' as your Site Path. Not 'Site1'
2) Make sure your Root folder actually exist. If your root folder name is 'abc', go to your control panel -> Files on the top menu to make sure it actually exist.