package: 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/package - from package: mailagent

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

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