unicode_stop: command not found

Have You tried accessing the binary with the full path?

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:

/bin/unicode_stop - from package: kbd

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

On Debian possible default full paths are:

/usr/bin/unicode_stop - from package: kbd

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