Using wordaxe 1.0.1.
The assert in NewParagraph.py:669 fails very often.
I don't understand the code well enough to figure it out, but something seriously bogus is going on.
Here's the code fragment:
self.width = availW
self.height = sumHeight
print sumHeight, availH
if sumHeight > availH:
assert not lineFrags, lineFrags
Here's the values of sumHeight, availH and lines in one run of rst2pdf before the assert fails:
0 -5.62834645669 
So, if I undestand correctly, there are no more lines, no space is required, and yet it's still trying to fit part of the unexistant remainder of the paragraph?
Hacking blindly it seems that changing the if to
if sumHeight > max(availH,0):
and removing the assert at the end of the method makes wordaxe work correctly, but I may be breaking everything in another way.