Recommend the software, I must say. but its a monster, itll chew up all my 1GB of RAM and eat another gig of swap easily, and I dont do full-res pictures with it, my system cant handle them at all
Im half tempted to order another GB, if I get serious about this sort of thing
You need to add some extra horizontal control points to correct the bend in the land - dont rely on the automagick for vertical and horizontal detection.
The blending stage, if its making use of enblend, will eat up disk space in the current working directory after 1gig of memory has been used (default enblend behaviour modified via the -m flag), so make sure there is plenty of disk space available.
Also, check to see if it is making use of enblends -a option as this will, while increasing the amount of memory needed, reduce the number of blend steps and thus the blend will finish much sooner.