Honestly I have next to no experience with C++ Builder. But as far as I know, C++ builder doesn't use the Delphi project and package files. Here are some things that you possibly can try:
- Try to use the project files (ZComponent.cbproj etc.) in the cbuilder12 directory
- Remove the *.cbproj files and try to open the projects using the *.bpf files. If C++ Builder works like Delphi it will regenerate the *.cbproj files from there.
Jan