FumeFX and AB shadow map: illumination map freeze

[jstrob2]

When I have hi-rez fume fx grid (approx 450x700x500) and I use AB shadow map on 2 lights (with raytrace shadows for object shadows), I often get the problem of the render getting frozen on the first pass of the illumination map calculation. the freeze seems to occur randomly on different frames and the more I incresase the resolution of the grid, the more it occurs to the point of occuring everytime if the rez is too large. Is there any tips to avoid that?

(I'm rendering with scanline).