If you are upgrading then there should not have been a need to change file/folder permissions.
You would have just overwrote the files when you uploaded them.
Normally the file permissions would not be changed.
But some host do not allow 777 and you would need to change it to 755.
And even though you will navigate to the install folder it would be upgrade.php you run not install.php.
So if you got lost on file permissions follow the install guide
https://www.ubbcentral.com/doc_install.phpThen if needed use 755 where it indicates 777.
