Go back to http://forums.adobe.com/community/encore and, in the area just under Ask a Question, type in
mavericks
You may now read all the previous discussions on this subject... be sure to click the See More Results at the bottom of the initial, short list if the initial list does not answer your question
I am Windows so did not bookmark the message, but at least one message thread has a possible solution for SOME mavericks problems - NOTE
But, do be aware that a note in http://www.adobe.com/products/encore/faq.html states that Adobe will NOT provide Encore updates for newer operating systems
NOTE... you may need to go to http://forums.adobe.com/community/premiere and repeat the mavericks search to find help... there have been a LOT of discussions there