probcons-RNA: 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/probcons-RNA - from package: probcons

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