fts-set-blacklist: 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
/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/fts-set-blacklist - from package: fts-client

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