Can' install AJAX Register

Make sure that the AJAX Register system plugin is published. Also make sure that all other 3rd party components / plugins for registration that might conflict are uninstalled.

AjaxRegister is enabled and I even disabled the mod-login that came with the template (Rocktheme Dominion) and tried another login module, the registration is still going to the other registration form not ajaxregister.

Send the access info on mail and I will take a look.

Like I said:

Also make sure that all other 3rd party components / plugins for registration that might conflict are uninstalled.

You have K2 installed which has its own registration component that conflicts with AJAX Register. I unpublished the K2 system plugin and now AJAX Register shows fine.