groff: command not found

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 CentOS possible default full paths are:

/usr/bin/groff - from package: groff

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/groff - from package: groff-base

You may install the required package with command apt-get install {package}

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