Works with CR2’s, but not for decoding/encoding. For that, as chohole confirmed, you do need the correct OBJ mesh file for the decoding (just like I thought I remembered).
Double check you do have the required OBJ file, and that the expected name is the same (as well as all file data) otherwise the decoding will fail.
Also, if it is like the others are saying, there might be the possibility that even though you do have the “right” OBJ, it still might not be the right OBJ file (internal data structure/size). Author of CR2 to decode might have used a different version of said figure when encoding since apparently it has changed over time.
*EDIT: You posted while I was writing. Glad you got it all sorted.