edg-gridftp-exists: 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

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/edg-gridftp-exists - from package: edg-gridftp-client

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