cntraining: 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/cntraining - from package: tesseract-ocr

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

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