Norm is right.
Probably the easiest way to fix this is to go to the .mis file in your campaign and missions folders and open up the missions with the Centauro with Wordpad or Notepad and change each occurrence of the Centaruro to match your Centauro folder's name exactly.
Example:
[unit_type.1]
type_id=3816
unit_family=1
name=FIAT_G55_CENTAURO <<This must match your plane folder
If you are using Wordpad, you can use the search function to search out all mention of the Centauro in your .mis files and udate them accordingly.
If you change your plane's folder name to match the missions, then you'll loose the plane in your Quick Combat menu, although that's another way to fix the problem in your campaign.
A lot of CFS 2 is interconected in various files and folders. If the names do not match in them, then you get problems like the one you're having now.