Comment 9 for bug 526259

I tested on three XP machines and a Win7RC, but could not reproduce the error.

So the good new is, the problem does not occur on all Windows machines.
The bad news is, I have no system to test bugfixes on.

I found where someone else ran into the same error. Try his instructions, then run Keryx again from source: http://blog.oneortheother.info/tip/python-fix-cp720-encoding/