Those who get the message that you should use PC, it means that you have conflicting packages and application manager is trying to be nice and not force-remove them. You should probably remove potential blockers (anything from devel is a good candidate) and try again. You can also use apt-get which may or may not work (and you need to reboot at the end yourself). You should also use command df to see how much free space you have on device before resorting to apt-get. Using apt-get will need more than that 45 megs of space. Probably 50 megs is enough though, but I'm not sure. If you run out of space, do not reboot, but free first more space and then continue with apt-get