glite-lb-migrate_db2version40: 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/sbin/glite-lb-migrate_db2version40 - from package: glite-lb-server

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

Error in other languages:
glite-lb-migrate_db2version40: bevel nie gevind nie
glite-lb-migrate_db2version40: comandă negăsită
glite-lb-migrate_db2version40: comando não encontrado
glite-lb-migrate_db2version40: commande introuvable
glite-lb-migrate_db2version40: command not found
glite-lb-migrate_db2version40: käsku ei ole
glite-lb-migrate_db2version40: không tìm thấy lệnh
glite-lb-migrate_db2version40: komanda nerasta
glite-lb-migrate_db2version40: Kommando nicht gefunden.
glite-lb-migrate_db2version40: kommandot finns inte
glite-lb-migrate_db2version40: komut yok
glite-lb-migrate_db2version40: nie znaleziono polecenia
glite-lb-migrate_db2version40: níor aimsíodh an t-ordú
glite-lb-migrate_db2version40: no se encontró la orden
glite-lb-migrate_db2version40: no s'ha trobat l'ordre
glite-lb-migrate_db2version40: opdracht niet gevonden
glite-lb-migrate_db2version40: parancs nem található
glite-lb-migrate_db2version40: perintah tidak ditemukan
glite-lb-migrate_db2version40: príkaz nenájdený
glite-lb-migrate_db2version40: příkaz nenalezen
glite-lb-migrate_db2version40: команда не найдена
glite-lb-migrate_db2version40: командата не е открита
glite-lb-migrate_db2version40: 命令找不到
glite-lb-migrate_db2version40: コマンドが見つかりません