The FTP Client Filezilla has a recursive option, where you can right click a selection of files/folders and tell it to chmod all folders 777, then reselect and chmod all files 666; then you don't need to do anything manually.
I'm not asking anything having to do with docs, again, every file is required, v7.6 was a MAJOR UPGRADE. Without telling me anything about the install or upgrade documentation, what files did you actually not upload (other than the three I keep stating), it's extremely important.