vecscreen: 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

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/vecscreen - from package: ncbi-tools-bin

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