mwcontam: 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/mwcontam - from package: emboss

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

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