time-admin: 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/time-admin - from package: gnome-system-tools

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

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