op2calltree: 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/op2calltree - from package: kdesdk

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

On Debian possible default full paths are:

/usr/bin/op2calltree - from package: kcachegrind-converters

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

Error in other languages:
op2calltree: bevel nie gevind nie
op2calltree: comandă negăsită
op2calltree: comando não encontrado
op2calltree: commande introuvable
op2calltree: command not found
op2calltree: käsku ei ole
op2calltree: không tìm thấy lệnh
op2calltree: komanda nerasta
op2calltree: Kommando nicht gefunden.
op2calltree: kommandot finns inte
op2calltree: komut yok
op2calltree: nie znaleziono polecenia
op2calltree: níor aimsíodh an t-ordú
op2calltree: no se encontró la orden
op2calltree: no s'ha trobat l'ordre
op2calltree: opdracht niet gevonden
op2calltree: parancs nem található
op2calltree: perintah tidak ditemukan
op2calltree: príkaz nenájdený
op2calltree: příkaz nenalezen
op2calltree: команда не найдена
op2calltree: командата не е открита
op2calltree: 命令找不到
op2calltree: コマンドが見つかりません