DMX is the default now.

Solidify is designed to turn 2D surfaces into 3D volumes. I suspect that what you want to do is select certain edges and scale them up, possibly constraining the scaling axis.

Yeah, this is a hard-to-debug change in 2.68. Try using this test release[code.google.com], it should fix things.

Fixed: http://code.google.com/p/blender-smd/downloads/list