The directory tmp does not exist and could not be created
You didn't mention the actual (complete) value for the path of the "Temporary directory" you want to use. But something that should work, pretty sure, is like so:


Navigate (in your web browser) to relative path admin/config/media/file-system.
Copy the value you have entered for "Public file system path", assume it's some/path/files.
Paste the copied value (like some/path/files) in the field "Temporary directory", and append to that value something like /temp, so that it becomes something like  some/path/files/temp/
Hit the Save configuration button and you should be good to go (Drupal will, automagically, take care of the rest).