descseq: 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/descseq - from package: emboss

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

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