start_server: 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/bin/start_server - from package: libserver-starter-perl

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

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