arcmigrate: 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/arcmigrate - from package: nordugrid-arc-client

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

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