arcproxy-ui: 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-ui - from package: arc-gui-clients

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

On Debian possible default full paths are:

/usr/bin/arcproxy-ui - from package: arc-gui-clients

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

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