fusioninventory-netdiscovery: 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/fusioninventory-netdiscovery - from package: fusioninventory-agent-task-network

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

On Debian possible default full paths are:

/usr/bin/fusioninventory-netdiscovery - from package: fusioninventory-agent-task-network

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

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