hi, every one

I want to use the Equilibrium module to calculate the phase equilibria of CO2 and alkanes. First, I built a cubic CO2 cell and a cubic cell of hexane using amorphous module, then the hexane cell and CO2 cell

were selected as the box1 and box2 respectively in the Equilibria Mixture Gibbs. When the "run" is clicked a error occur, it seems that the NERD forcefield does not contain the "C=O" bond. The help file show

that I can chose the other forcefield, so I select the COMPASS forcefield to calculate this job, but some error also occured. Can someone help me and told me how to select the forcefield to calculate the phase

equilibria of CO2 and alkanes ?