Chamfer and fillet

Hi, my Name is Christ and I from D.R. my question is:
I am not able to perform a Chamfer nor Fillet on this curve (the one on the attached file) and I would like to know why.
THANK YOU ADVANCE

Hi Christian - can you please post the two curves in a Rhino file?

thanks,

-Pascal

HI, Pascal Thank you so much for your attention, but now I know what was happening. The curves were at different height.