d48: 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/d48 - from package: d52

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

On Debian possible default full paths are:

/usr/bin/d48 - from package: d52

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

Error in other languages:
d48: bevel nie gevind nie
d48: comandă negăsită
d48: comando não encontrado
d48: commande introuvable
d48: command not found
d48: käsku ei ole
d48: không tìm thấy lệnh
d48: komanda nerasta
d48: Kommando nicht gefunden.
d48: kommandot finns inte
d48: komut yok
d48: nie znaleziono polecenia
d48: níor aimsíodh an t-ordú
d48: no se encontró la orden
d48: no s'ha trobat l'ordre
d48: opdracht niet gevonden
d48: parancs nem található
d48: perintah tidak ditemukan
d48: príkaz nenájdený
d48: příkaz nenalezen
d48: команда не найдена
d48: командата не е открита
d48: 命令找不到
d48: コマンドが見つかりません