profnet_con: 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/profnet_con - from package: profnet-con

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