I get an error with secondscreen on gem 0.87, but not on a new gem version (gem 0.87 + cvs (compiled april 14 2003)). maybee upgrading your gem version will help. (?)
secondscreen only works on OSX - that's the only platform Jamie and I wrote it for. on the various windows platforms you can feed the coords of the second display and turn off the border for the gemwin. this may or may not give an accelerated context depending on hardware.
Cyrille