lmt-config-gui: 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/sbin/lmt-config-gui - from package: laptop-mode-tools

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