[help]the RL interaction: is 2D structure for the ligand OK?

Hi,
I'm using DS2.0, we have the license right to the CDOCKER and LigandFit in the RL protocles. I don't have the 3D structures for my ligands. I have tried several times with 2D files, but the protocal could not run succesfully. My input ligand file is sdf, is there anything wrong or must I prepare 3D structure for ligand?
Thank you very much!