learnkeys: 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

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/learnkeys - from package: esekeyd

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