seedtop+: 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/seedtop+ - from package: ncbi-blast+

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