bp_seqconvert: 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_seqconvert - from package: bioperl

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