inject-users.php: 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/share/gforge/bin/inject-users.php - from package: gforge-db-postgresql

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

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