dtdinst: 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/dtdinst - from package: dtdinst

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

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