Havent looked at your file, but on the popsolver DOP there are a few things you may need to check. Set the 'Rehome Particles' to 'Left Most Generator' This makes sure the particles are 'owned' by a given pop. Without it, the particles get ignored. You probably want to uncheck 'Handle Collisions' under the collision tab. You can also set if you want to pop to only effect the velocity or accel (force) on the solver tab > Solve Mode. Typically, I set this to Update Velocity, but note if you do this AFAIK, POPs which modify force will have no effect ie Drag, Force, etc
Hope this helps