arcacl: command not found

Have You tried accessing the binary with the full path?

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/arcacl - from package: nordugrid-arc-client

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