Lightning is a Thunderbird extension to provide a calendar and a task list like Microsoft Outlook does.
When using Lightning with new Ubuntu versions the new calendar entry in the pull down menu might be grayed out and one will not be able to create new calendars and dates.
Thunderbird relies itself on the shared library libstdc++5. This packages is no more installed by default in new Ubuntu versions. To fix it simply type:
apt-get install libstdc++5
Restart Thunderbird and reinstall Lightning to make it run.
Did it work for you? Drop a comment!