you need to be logged as Root to be able to edit most of the files, you need to enable root login via ssh,

Pre PR1.1

1. open xterm
2. devel-su [enter] then your root password [enter]
3. nano /etc/ssh/sshd_config

then use the arrowkeys on the virtualkeyboard to navigate the file to "Authentication" section and change 'permitRootLogin' to yes

once done, ctrl+o then enter saves the file
ctrl+x closes Nano