hmmc2: 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/hmmc2 - from package: hmmer

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

Error in other languages:
hmmc2: bevel nie gevind nie
hmmc2: comandă negăsită
hmmc2: comando não encontrado
hmmc2: commande introuvable
hmmc2: command not found
hmmc2: käsku ei ole
hmmc2: không tìm thấy lệnh
hmmc2: komanda nerasta
hmmc2: Kommando nicht gefunden.
hmmc2: kommandot finns inte
hmmc2: komut yok
hmmc2: nie znaleziono polecenia
hmmc2: níor aimsíodh an t-ordú
hmmc2: no se encontró la orden
hmmc2: no s'ha trobat l'ordre
hmmc2: opdracht niet gevonden
hmmc2: parancs nem található
hmmc2: perintah tidak ditemukan
hmmc2: príkaz nenájdený
hmmc2: příkaz nenalezen
hmmc2: команда не найдена
hmmc2: командата не е открита
hmmc2: 命令找不到
hmmc2: コマンドが見つかりません