listfonts: 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/listfonts - from package: libcam-pdf-perl

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

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