remuco-okular: 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/remuco-okular - from package: remuco-okular

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

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