ABAQUS HEX MESHING - HELP NEEDED

Hi,

 I am trying to mesh a solid in CAE using HEX elements. For some reason, I am getting an error message saying that the element topology is not right for the geometry.

 I eventually want to do crack analysis and so hex or wedge elements are essential for my model. Could anyone please help me and let me know if there is a way to go around the problem and get a hex mesh on the solid. I am attaching the .jpeg file of the geometry of the solid I want to HEX mesh.

Thanks a lot in advance