gpaco: 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/gpaco - from package: gpaco

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

On Debian possible default full paths are:

/usr/bin/gpaco - from package: gpaco

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

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