$ sudo apt-get update
$ sudo apt-get install libqthelp4-perl 

libqthelp4-perl is installed in your system.

Make ensure the libqthelp4-perl package were installed using the commands given below,

$ sudo dpkg-query -l | grep libqthelp4-perl *

You will get with libqthelp4-perl package name, version, architecture and description in a table

libqthelp4-perl package basic information: