The whole of the Ichelus region (the Volcano - a Linden Department of Public Works build) appears to be set so that landmarks cannot be created there. It's a picturesque build I like to use to demonstrate SL, and not being able to keep a landmark handy/hand out a landmark is annoying - is this intentional, and can it be changed?

SLURL: http://slurl.com/secondlife/Ichelus/188/231/50