Thanks Oscar, but I got it mostly working. On the Mac, Inkscape runs on top of another application XQuartz X11, and it appears to be an issue with how the two interact. If anyone else on a Mac is having trouble getting it to work I can walk you through what I did to make it work.
But anyway, any suggestions for online tutorials geared more to how we would use Inkscape to make maps? More on the practical side of drawing lines and manipulating objects, and less on the artistic stuff.