Hi Mohan,
The error message indicates that you used a template InfoObject for the field settings. You cannot override this. I suggest to delete the template InfoObject and define the field settings yourself.
Re. the last remark that you are dealing with a characteristic, the only option I see is to delete the decimals in the transformation. I don't think you can work with a key figure-like field but maybe try it. I think that the mapping from a characteristic to key figure won't work. My suggestion is that you have to work with a character-like field and remove the decimals in the transformation (a small ABAP routine will do the trick I suppose).
Best regards,
Sander