ocr4gamera: 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/ocr4gamera - from package: python-gamera.toolkits.ocr

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

Error in other languages:
ocr4gamera: bevel nie gevind nie
ocr4gamera: comandă negăsită
ocr4gamera: comando não encontrado
ocr4gamera: commande introuvable
ocr4gamera: command not found
ocr4gamera: käsku ei ole
ocr4gamera: không tìm thấy lệnh
ocr4gamera: komanda nerasta
ocr4gamera: Kommando nicht gefunden.
ocr4gamera: kommandot finns inte
ocr4gamera: komut yok
ocr4gamera: nie znaleziono polecenia
ocr4gamera: níor aimsíodh an t-ordú
ocr4gamera: no se encontró la orden
ocr4gamera: no s'ha trobat l'ordre
ocr4gamera: opdracht niet gevonden
ocr4gamera: parancs nem található
ocr4gamera: perintah tidak ditemukan
ocr4gamera: príkaz nenájdený
ocr4gamera: příkaz nenalezen
ocr4gamera: команда не найдена
ocr4gamera: командата не е открита
ocr4gamera: 命令找不到
ocr4gamera: コマンドが見つかりません