Password and vacation mode
I can no longer log in to a nation I am looking after for a while.
Is it perhaps possible that you cannot change your password when a nation is on vacation mode?
Vacation mode has nothing to do with password changes. The only thing that will cause your password to change is you visiting your nation settings, or using the forgot password (http://www.nationstates.net/page=forgot_password) link behind the login page.
As for the rest of your question, you need to rephrase. I don't understand what problem you are having. If you're simply saying your session times out after a while, it does that for most people. It depends on both your nation settings, your forum settings, and your browser settings. My money is on your browser, about which we can do nothing whatsoever.
I think that someone is letting him watch their nation while they can't get to a computer and he needs the password or something. It is kinda hard to understand...
I am looking after a nation, yes. I know the password since that person gave it to me. I know it is correct because I did log in several times. But now I can no longer log in, pisses me off.