genrestr_d: 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/bin/genrestr_d - from package: gromacs

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

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