Keyed particles working strange

Hello everyone!

I’m trying to achieve a very simple task - make a titles of a dust. I created two particle systems - one with no physics, other with some kind of simple animation - and selected them as keys for third particle system. But for some reason this keyed particles going crazy at all: they starts not on the first target system but in random locations throughout the space, sometimes they are generated in clumps and sometimes in one stream (as supposed to) and so on.
I have tried dozens of different settings regarding timestep, animating target systems, absolute amounts of particles and relative amounts to each other - no success at all. =( I even can’t figure any corellations between settings and particles behavior.
Can, please, anybody help me to figure, what am I doing wrong and how to achieve desired result?
I’m using blender 2.68.0 r58368
Blend-file is on my Dropbox (it’s 16MB and can’t be attached here): https://dl.dropboxusercontent.com/u/25108066/dust-particles_test_broken.rar
Thanks in advance!