bp_seqpart: 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_seqpart - from package: bioperl

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