kadmin.heimdal: command not found

Have You tried accessing the binary with the full path?

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/kadmin.heimdal - from package: heimdal-clients

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