spnavd_ctl: 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/spnavd_ctl - from package: spacenavd

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

On Debian possible default full paths are:

/usr/bin/spnavd_ctl - from package: spacenavd

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

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