bp_seqret: command not found

Have You tried accessing the binary with the full path?

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/bp_seqret - from package: bioperl

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