The compiler is reporting errors (you can check the "Console" view after building). The errors reported in the “Console” view are taken by IDE, parsed and displayed in the "Problems" view.
It seems that the project that is reporting fewer errors has disabled the Error Parsers for Metrowerks tools.
If you enable these in the
Project -> Properties -> C/C++ Build -> Settings -> Error Parsers tab, by checking the
Metrowerks Error Parser
Metrowerks Front End Error Parser
you will see all the errors reported by the compiler (which are more than on the other project).