install-apache.sh: 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/install-apache.sh - from package: gforge-web-apache2

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

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