kstartperf: 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/kstartperf - from package: kdesdk

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

On Debian possible default full paths are:

/usr/bin/kstartperf - from package: kdesdk-misc

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

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