Do you have JomSocial installed? If yes, you must re-configure your CA menu items everytime you install JomSocial. JomSocial will remove all menu items that starts with "community" and re-create with its own. So your page url
No, no component of that type, even CB
only the user profile plugin and Kunena joomla 2.5.4 to manage profile.
After writing this I thought perhaps the breadcump of joomla that is only visible to registered could be bothersome and time is disabled by your component.
joomla sef is active with htaccess on, and nothing else.
Can you check from where such urls are being generated? The only way the urls like component/com_communityanswers/view/1-blah.html are generated if the menu item is not configured properly. This is standard Joomla behavior. Joomla will reference the component urls directly in above format if the proper menu item not found.