tdc: 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/tdc - from package: tdc

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

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