From Ring of Brodgar

Unable To Trespass

I have the "Ranging" skill acquired and "criminal acts" enabled, although I cant get into some claims with "that land is owned by someone" message. --Trepach 06:44, 29 February 2012 (EST)

Trespassing is a Skill, as such it must be purchased before you can actually access a personal claim that you have no "legal" access to. Ranging does not allow you to commit any crimes only to track them. In all honesty i think both are obvious from their respective pages. --Rook 07:07, 29 February 2012 (EST)
I cant have "Ranging" if I dont have "Trespassing". And still I am unable to trespass.
Ok, I understand you think there is something wrong with the info here, but you're wrong in this case. Again refering you to Skills page, and respective pages for Ranging and Trespassing, you can follow their "skill(s) required" links. Alternatively there's a skill tree on the Skills page. In both cases the conclusion is this:
Ranging <- Valor <- Unarmed Combat <-The Will to Power <- Wilderness Survival
Trespassing <- The Will to Power <- Wilderness Survival
Therefore my assumption is, again, you lack the Trespassing skill. --Rook 11:17, 29 February 2012 (EST)

Trepach.. If you would have searched the HnH forum a bit, you would have found that you only need to activate "criminal acts" to be able to walk onto someone else his claim (for which you don't have free access).. The message "that land is owned by someone" is in this case a warning message informing you that you are about to walk into a claim for which you don't have trespassing rights.. (With that warning your initial attempt to walk onto that claim is of course blocked (with or without having "criminal acts" activated), or else it would be kinda useless (as warning). Any additional attempt to enter that claim, when "criminal acts" is active, will succeed..
(Seems this message is also used in other situations/actions. Probably because the character I used had no additional criminal skills.)
(Wiki can, of course, use some additional info on this.)
--MvGulik 13:50, 29 February 2012 (EST)