lockfile: 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/lockfile - from package: procmail

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

On Debian possible default full paths are:

/usr/bin/lockfile - from package: procmail

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

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