You need to check that check box and specify Admin as the user name with the password box left empty.
There's an option in File OPtions for selecting a layout as the first layout seen when the file opens. Has that worked for you? If not, check for a script that is interfering. A OnRecordLoad or OnLayoutEnter trigger on a layout or a script set to run when when the file opens may be superceding the specified "onOpen" layout.
OK, the checking the password box in File Options solved the password issue. I also checked the box to have it open to the layout "Cover Page" but it does not work. I am aware of event triggers in the layout mode but I have checked none of them. I have no scripts that have anything to do with the opening or closing of the file. I thought about havinig a script to go to cover page and then close the file, but that's just another thing to have to do and the button would have to appear in all layouts.
I use File OPtions to specify an inital layout when the file is opened all the time and it works. You'll need to figure out why it isn't in your case. Best guess is kicking in to change the layout on you. A layout based script trigger is one possibility, a script set in file options to run when the file is opened is another.
If you have FileMaker Advanced, I'd open FileMaker without opening this file, enable the script debugger and then use Open from the file menu to open the file and watch to see what happens when the file opens step by step.
Note: you can specify that FileMaker run a script when the file is closed and it can switch to a layout--which won't need you to use any buttons on any layout, but if a script is interferring here like I suspect, that won't work for you.