lmtptest: 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/lmtptest - from package: cyrus-imapd-utils

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

On Debian possible default full paths are:

/usr/bin/lmtptest - from package: cyrus-clients

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

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