Built for Intel Mac on Leopard.
Please log issues on the gears developer website (http://code.google.com/p/gears/issues/list). Make sure to include the gears version number and the svn revision number in your report. These are both encoded in the download filename so for:
gears-osx-dbg-0.5.27.0_r3381.xpi
Gears version is 0.5.27.0 and the svn revision is 3381.