sane-config: 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/sane-config - from package: sane-backends-devel

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

On Debian possible default full paths are:

/usr/bin/sane-config - from package: libsane-dev

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

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