Sounds like your missing files.  The archive is setup to be put up into the root HCL directory.  Note however that eTicket isn't behaving at all, and there is some question if it will be continued.  It simply is not at a production stage, and there seems to be some issues building in their forums about issues being ignored that have been shown to corrupt it's MySQL tables.

I had hoped that eTicket would be fairly seamless, however it now appears that there is almost as many bugs in eTicket as osTicket (albeit they don't seem to cause the server to be compromised). 

I'm not saying that with time they will get everything sorted out, but at this point there is exactly one coder on Help Center Live, and I have to pick my fight, so to speak.  Fixing their issues isn't on the agenda, at this point my best advice is to disable eTicket until we see if they come up with a fix for the DB issue.

Until then, I'd be happy to help you sort this issue out.
 

includes is part of the HCL core. 

You should have the following inside of the zip file:

modules/
    eTicket/
        attachments/
        hcl/
        inc/
        install/
        themes/
        admin.php
        attachments.php
        automail.php
        automail.pl
        captcha.php
        help.php
        index.php
        init.php
        lang.php
        newticket.php
        open.php
        readme.html
        rss.php
        search.php
        settings.php
        view.php
templates/
readme1st.txt

I'm not going to list every file, since I'm hand typing it out.  But you get the idea.  If your eTicket directory doesn't have this, you need to go back and look at the zip file again.