ib_send_lat: 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:

/usr/bin/ib_send_lat - from package: perftest

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

On Debian possible default full paths are:

/usr/bin/ib_send_lat - from package: perftest

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