proxytrack: 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/proxytrack - from package: httrack

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

On Debian possible default full paths are:

/usr/bin/proxytrack - from package: proxytrack

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

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