dancer2: 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/dancer2 - from package: libdancer2-perl

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

Error in other languages:
dancer2: bevel nie gevind nie
dancer2: comandă negăsită
dancer2: comando não encontrado
dancer2: commande introuvable
dancer2: command not found
dancer2: käsku ei ole
dancer2: không tìm thấy lệnh
dancer2: komanda nerasta
dancer2: Kommando nicht gefunden.
dancer2: kommandot finns inte
dancer2: komut yok
dancer2: nie znaleziono polecenia
dancer2: níor aimsíodh an t-ordú
dancer2: no se encontró la orden
dancer2: no s'ha trobat l'ordre
dancer2: opdracht niet gevonden
dancer2: parancs nem található
dancer2: perintah tidak ditemukan
dancer2: príkaz nenájdený
dancer2: příkaz nenalezen
dancer2: команда не найдена
dancer2: командата не е открита
dancer2: 命令找不到
dancer2: コマンドが見つかりません