Terminal capability cm required

Problem:

Commands like vim / vi / crontab -e all throw an error about "terminal compatibility".
This is because your TERM value is set to "screen" as you are no doubt connecting to a box inside a screen session, or are just using screen.

Error:

"E437: terminal capability "cm" required"

Solution:

Quickest fix run: export TERM=xterm
Or if for some reason you are not connecting via screen, check your TERM variable by:
echo $TERM

If this doesnt work, then you need a terminal that supports ncurses. Easiest way is to just search your package manager for "ncurses". (I suggest tilda or gnome-terminal)