if ll you have is cli, you need to complete the update process
in cli write synaptic, it will ask root password, write it and then press reload button, after that press mark all updates and apply, after a successful update restart
if synaptic can't start you can use as last option apt-get dist upgrade, there is a couple of commands explained more details on this inconvenient situation
pclinux is a rolling release distro, you need to update everything, quite often
partial updates will create this situations
if none of the options i mentioned works, use livecd to backup your personal files and enjoy installing a new iso
