wpa_action: 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:

/sbin/wpa_action - from package: wpasupplicant

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

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