Unable to remove the packages in ubuntu

When I try to remove the virtual box installed on ubuntu as follow,

sachin-verma@sachin-verma:~$ sudo apt-get remove virtualbox-5.1

Then it shows following errors:

Reading package lists... Error! N: Ignoring file '50unattended-upgrades.ucf-dist' in directory '/etc/apt/apt.conf.d/' as it has an invalid filename extension N: Ignoring file 'getdeb.list.bck' in directory '/etc/apt/sources.list.d/' as it has an invalid filename extension E: Encountered a section with no Package: header E: Problem with MergeList /var/lib/apt/lists/in.archive.ubuntu.com_ubuntu_dists_xenial_main_binary-amd64_Packages E: The package lists or status file could not be parsed or opened.

Please help me out ?

PS.- This is also happening, when I am trying to uninstall other packages.