zforce: 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 CentOS possible default full paths are:

/usr/bin/zforce - from package: gzip

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/bin/zforce - from package: gzip

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

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