pt-fk-error-logger: 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 Debian possible default full paths are:

/usr/bin/pt-fk-error-logger - from package: percona-toolkit

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

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