ocs-chkimg: 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/sbin/ocs-chkimg - from package: clonezilla

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

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