Even if your an admin on each box, you still have to allow permissions for other boxes to have access. For example: If I have a share setup on computer A and I want to access it from computer B, I need to set the security of the share of Computer A for the user of Computer B to have access. If it's just your home network and you don't care which computers can get access to what, you can allow "everyone" to have full control. That way it won't matter who's logged in, you'll have permission. If you do that, just make sure that your router/firewalls are setup properly. If your still having trouble, disable mcafee temporarily just to rule it out as a problem.

Hope this helps