swaplabel: 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:

/sbin/swaplabel - from package: util-linux

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

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