nthseq: 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/nthseq - from package: emboss

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

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