show-coords: command not found

Have You tried accessing the binary with the full path?

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On Debian possible default full paths are:

/usr/bin/show-coords - from package: mummer

You may install the required package with command apt-get install {package}
Error in other languages:
show-coords: bevel nie gevind nie
show-coords: comandă negăsită
show-coords: comando não encontrado
show-coords: commande introuvable
show-coords: command not found
show-coords: käsku ei ole
show-coords: không tìm thấy lệnh
show-coords: komanda nerasta
show-coords: Kommando nicht gefunden.
show-coords: kommandot finns inte
show-coords: komut yok
show-coords: nie znaleziono polecenia
show-coords: níor aimsíodh an t-ordú
show-coords: no se encontró la orden
show-coords: no s'ha trobat l'ordre
show-coords: opdracht niet gevonden
show-coords: parancs nem található
show-coords: perintah tidak ditemukan
show-coords: príkaz nenájdený
show-coords: příkaz nenalezen
show-coords: команда не найдена
show-coords: командата не е открита
show-coords: 命令找不到
show-coords: コマンドが見つかりません