gtester: 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/gtester - from package: glib2-devel

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

On Debian possible default full paths are:

/usr/bin/gtester - from package: libglib2.0-dev

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

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