regina: 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/regina - from package: regina-rexx

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

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