aconnectgui: 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/aconnectgui - from package: aconnectgui

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