Thanks for reporting as @pkiller mentioned this should be fixed if you create the system folder. I have also fixed it on master as well as the error messages so you should get a better error message if the upload fails.
Correct me I am wrong, as of now we can post only a particular board, right ? We can simply change the no. 4 /5 or one of our choice. Also Custom home page header vanishes when I click the logo button.