I recently replaced my multisite Wordpress site with a new one that I built on a subdomain. The new one is a simple, one domain site. Everything is working properly, including the Civicrm that I was using with my old site except for the online registration for CiviEvent.

When someone clicks on a link to register for an event, instead of going to the register page:
<http://newsite/?page=CiviCRM&q=civicrm/event/register&reset=1&id=numberofevent>

it defaults to the info page:
<http://newsite/?page=CiviCRM&q=civicrm/event/info&reset=1&id=numberofevent>

and gives this error message:
*Sorry but we are not able to provide this at the moment. 
You do not have permission to access this page*

Hint: when I go into the Wordpress admin area of the site on a specific browser, I can get the links to take me to the registration page without a problem. 

Two more points:
When it defaults to the info page with error message, the "/" turns to "%2F"

Also, the same problem occurs for profiles. when I use the "Profile Create Mode" to view the profile, it works on the browser where I am logged in, but on a browser where I am not logged in, I get an error message:

Sorry but we are not able to provide this at the moment.
*The requested Profile (gid=numberofprofile) is disabled OR it is not configured to be used for 'Profile' listings in its Settings OR there is no Profile with that ID OR you do not have permission to access this profile. Please contact the site administrator if you need assistance.*