New software can't be installed, because there is a problem with the software currently installed. Do you want to repair now? hit Repair Package operation failed The installation or removal of a software package failed. Details => installArchives()failed:Could not exec dpkg! Error in function (synaptic:12725): GLib-CRITICAL **: g_child_watch_add_full: assertion 'pid > 0' failed Could not exec dpkg! E: Sub-process /usr/bin/dpkg returned an error code (100) A package failed to install. Trying to recover: sh: 1: dpkg: not found