data_maintainer3: 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/data_maintainer3 - from package: skytools3

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

Error in other languages:
data_maintainer3: bevel nie gevind nie
data_maintainer3: comandă negăsită
data_maintainer3: comando não encontrado
data_maintainer3: commande introuvable
data_maintainer3: command not found
data_maintainer3: käsku ei ole
data_maintainer3: không tìm thấy lệnh
data_maintainer3: komanda nerasta
data_maintainer3: Kommando nicht gefunden.
data_maintainer3: kommandot finns inte
data_maintainer3: komut yok
data_maintainer3: nie znaleziono polecenia
data_maintainer3: níor aimsíodh an t-ordú
data_maintainer3: no se encontró la orden
data_maintainer3: no s'ha trobat l'ordre
data_maintainer3: opdracht niet gevonden
data_maintainer3: parancs nem található
data_maintainer3: perintah tidak ditemukan
data_maintainer3: príkaz nenájdený
data_maintainer3: příkaz nenalezen
data_maintainer3: команда не найдена
data_maintainer3: командата не е открита
data_maintainer3: 命令找不到
data_maintainer3: コマンドが見つかりません