Try using the Unfold option instead try setting the Weight and Opitmize to .5 for starters. In your UV editor select 1 UV vertex in the middle of the mesh, uncheck pin UV border, Pin UV's - Pin Selected and Unfold contrain at None. Max Iterations at 10000 stopping threshold at .001 for starters. Rember you sometimes will have to apply this a number of times with differnt settings to get a decent looking layout.
Relax isnt really meant for prmary UV layouts, its more for averaging out UV's after you have a good layout. Usuallu pin a selcted UV try differnt Edge weights (world usually works well) and start with a low iteration.