scanner: 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/scanner - from package: mirrorbrain-scanner

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

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