avr-gprof: 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/avr-gprof - from package: avr-binutils

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

On Debian possible default full paths are:

/usr/bin/avr-gprof - from package: binutils-avr

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

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