g_editconf: 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/g_editconf - from package: gromacs

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

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