gputest_benchmark: 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/lib/plainbox-providers-1/checkbox/bin/gputest_benchmark - from package: plainbox-provider-checkbox

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

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