manage-apache-config.sh: command not found

Have You tried accessing the binary with the full path?

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/manage-apache-config.sh - from package: gforge-web-apache2

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