mstflint: 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/mstflint - from package: mstflint

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

On Debian possible default full paths are:

/usr/bin/mstflint - from package: mstflint

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

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