net-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 CentOS possible default full paths are:

/usr/bin/net-server - from package: perl-Net-Server

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

On Debian possible default full paths are:

/usr/bin/net-server - from package: libnet-server-perl

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

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