roff2dvi: 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 Debian possible default full paths are:

/usr/bin/roff2dvi - from package: groff

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

Error in other languages:
roff2dvi: bevel nie gevind nie
roff2dvi: comandă negăsită
roff2dvi: comando não encontrado
roff2dvi: commande introuvable
roff2dvi: command not found
roff2dvi: käsku ei ole
roff2dvi: không tìm thấy lệnh
roff2dvi: komanda nerasta
roff2dvi: Kommando nicht gefunden.
roff2dvi: kommandot finns inte
roff2dvi: komut yok
roff2dvi: nie znaleziono polecenia
roff2dvi: níor aimsíodh an t-ordú
roff2dvi: no se encontró la orden
roff2dvi: no s'ha trobat l'ordre
roff2dvi: opdracht niet gevonden
roff2dvi: parancs nem található
roff2dvi: perintah tidak ditemukan
roff2dvi: príkaz nenájdený
roff2dvi: příkaz nenalezen
roff2dvi: команда не найдена
roff2dvi: командата не е открита
roff2dvi: 命令找不到
roff2dvi: コマンドが見つかりません