arcproxy: 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 CentOS possible default full paths are:

/usr/bin/arcproxy - from package: nordugrid-arc-client

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/arcproxy - from package: nordugrid-arc-client

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

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