I am trying to connect to my mac mini running Mac OS X 10.6.7. I have turned on Screen Sharing with a password. On my xp machine I am using ultravnc to connect. I can put in the address of the mac mini and it will ask for my password and I enter it and hit enter. A box big box will flash for a split second and go away and then I am back to my desktop. How do I get this to work?