Please note that you are trying to upgrade from 14.04 -which is indeed an LTS version- to 14.10, which is not LTS.
Since 14.04 is still supported, most of your software is up to date to much the same way as if you went to 14.10. So there is no real need to upgrade. Please note, 14.04 will be supported until April 2019, and 14.10 only up to July this year, so you are in fact taking a step backwards.
If this is a production machine, I would strongly recommend staying with 14.04 until the next LTS version rolls along.
On the other hand, if this computer is just for testing and all your personal data is fully backed up, you could consider trying the following:
- as root, edit manually the file
/etc/apt/sources.list, replacing all occurrences of
sudo aptitude update
sudo aptitude safe-upgrade
This procedure has been known to work to upgrade between Debian versions. It will take quite some time and download in excess of 600 MBytes for a base Ubuntu system (more if more software is installed), but if it succeeds will leave you with a Utopic (14.10) system with the same selection of software you currently have installed.
I would not recommend trying to upgrade directly to Vivid (15.04), since the change from upstart to systemd may very well have changed system package dependencies sufficiently to completely mix up the software manager.