surely if you have complete ownereship of a plot of land you should be able to do anything you want in it as its your land,your own country where you are king, you nake the laws

theres probably a law about this but could someone plz point it out to me

Land ownership in the first place is defined by a national entity. If you really had your own country, there would be no need to "own" it.

The land may be yours, but there are rules and regulations about what you're allowed to do on it. Your lawyer can do a search and inform you of what's allowed.

The downside of trying to enforce such a thing is having to supply your own power, water, etc, etc or you'd have to rent it from the nation surrounding you - and they could refuse it out of spite. Also, you'll lose valuable protection. Law enforcement will be powerless to stop any crimes happening and you'll be offered no military protection. Sure you could kill people for fun, but that would probably break various international laws, you'll be invaded and you'll be executed for crimes against humanity. Win-win I think.

wasnt there a group in queensland that tried to declare sovereignty a while back?

Here are a few links for you to browse. One raises some valid points i.e. the state forces it's regime onto you immorally upon your birth.

http://permanenttourist.com/4paths/sovereignty.html

http://www.prfamerica.org/SupremeCourtDeniesOneidas.html

The top one I found most interesting as it raises alot of valid arguements.