The answer is in your post:
Code:
Zimbra server reserving server socket port=995 bindaddr=null ssl=true
Fatal error: exception while binding to ports
java.net.BindException: Address already in use
Something is using port 995. What does a 'zmcontrol status' show? SHutdown zimbra with 'zmcontrol stop' and see what's left running that might belong to Zimbra, kill it and restart zimbra - what happens?