kni_socketcontrol: 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

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/kni_socketcontrol - from package: libkni3-examples

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