[SOLVED] !!! Links Not Working

Hi, So I am new to the Bookings System.

After installing I created some menu items using the ready made Booking Menu Items such as employees, Our Services,  etc. But when I click on the link (Employees).. I see the one I added, but then I cant access his profile as it just sends me to a 500 Server error.
The same applies to most of the links. 

I can view the Calendar and calendar View but all second level links dont work. Such as employee Page, Employee Settings, Direct Appointment, Bookings etc.

I have Membership Pro on the same site (Joomla 5.2.2) and that works fine, regarding the redirects. 
SEF is one and URL Rewriting is on. 

Any ideas whats going on?

Thanks