refer.pl: 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/lib/wims/bin/refer.pl - from package: wims

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

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