Ubuntu – Muon package manager thinks that other package manager is open, and is not

I use KDE in Ubuntu 11.10 (I installed KDE with kubuntu-desktop using software center), which comes with muon package manager bundled, but some day Muon package manager decided not to update and giving an excuse 'that other package manager is already running'.

Another application seems to be using the package system at this time. You must close all other package managers before you will be able to install or remove any packages

I open krunner, nothing that is related with package managment is running as I can see in the processes running.

I did everthing what is posted here: http://kubuntuforums.net/forums/index.php?action=printpage;topic=3119344.0

And muon-updater/muon package manager refuses to install any updates.

I can install/uninstall with aptitude, apt-get with no error notifications, I can even upgrade packages with gnome's update manager, but that's not my case.

I don't have broken packages, as 'aptitude' doesn't tell me nothing about broken packages, neither muon, neither apt-get.

What else can I do in order to get muon installing/upgrading packages as usual?.

As Additional info: I upgraded KDE 4.7.2 to 4.7.3 through kubuntu-updates PPA, and I have 202 packages to upgrade but aptitude says that won't upgrade many packages because the upgrading will broke dependencies, that in every upgradeable package listed in aptitude.

I made in Konsole sudo apt-get update && sudo apt-get upgrade then it list the 204 packages that will upgrade but in the end says 204 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
Need to get 161 MB of files.
It used 233 kB of additional disk space after this operation.
Do you want to continue [Y / n]? I translated the apt-get message using google, this is the original in my native language: 204 actualizados, 0 se instalarán, 0 para eliminar y 0 no actualizados.
Necesito descargar 161 MB de archivos.
Se utilizarán 233 kB de espacio de disco adicional después de esta operación.
¿Desea continuar [S/n]?

this last might be the reason why muon can't upgrade anything?.