Thanks for your suggestions, folks.
Okay it works with package command just as TheoPetersen said. So special thanks to you

So now to the aspect of why to do it at all.
Many people have ISPs which are cheap but almost
certainly won't install new modules for their customers
(Or it just takes too long).
I think that's why UBB includes some modules with their program.
Also it's convenient not to have to ask your
sysadmin before you can use a script. I think that's a valid point.
As much as I love "clean" installations you can think of cases where it's
easier/faster just to include a module with a program (as long it's legally all right).

For example :
I wanted to test my script on an UNIX machine (I'm on Win32).
So I uploaded it to my ISP (who hasn't got HTML::Template or XML::Simple installed).
I know that my ISP would install new modules for me but by including these modules it was a little easier
for me and only took some minutes.

As I am not too much into UNIX I am not aware if there
might be technical difficulties arrising from doing this but I would be interested in hearing about that if this is the case.