ykneomgr: 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/ykneomgr - from package: libykneomgr

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

On Debian possible default full paths are:

/usr/bin/ykneomgr - from package: ykneomgr

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

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