exim4-localscan-plugin-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 Debian possible default full paths are:

/usr/bin/exim4-localscan-plugin-config - from package: exim4-dev

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

Error in other languages:
exim4-localscan-plugin-config: bevel nie gevind nie
exim4-localscan-plugin-config: comandă negăsită
exim4-localscan-plugin-config: comando não encontrado
exim4-localscan-plugin-config: commande introuvable
exim4-localscan-plugin-config: command not found
exim4-localscan-plugin-config: käsku ei ole
exim4-localscan-plugin-config: không tìm thấy lệnh
exim4-localscan-plugin-config: komanda nerasta
exim4-localscan-plugin-config: Kommando nicht gefunden.
exim4-localscan-plugin-config: kommandot finns inte
exim4-localscan-plugin-config: komut yok
exim4-localscan-plugin-config: nie znaleziono polecenia
exim4-localscan-plugin-config: níor aimsíodh an t-ordú
exim4-localscan-plugin-config: no se encontró la orden
exim4-localscan-plugin-config: no s'ha trobat l'ordre
exim4-localscan-plugin-config: opdracht niet gevonden
exim4-localscan-plugin-config: parancs nem található
exim4-localscan-plugin-config: perintah tidak ditemukan
exim4-localscan-plugin-config: príkaz nenájdený
exim4-localscan-plugin-config: příkaz nenalezen
exim4-localscan-plugin-config: команда не найдена
exim4-localscan-plugin-config: командата не е открита
exim4-localscan-plugin-config: 命令找不到
exim4-localscan-plugin-config: コマンドが見つかりません