E2212 Package unit '%s' cannot appear in contains or uses clauses (Object Pascal)
The unit named in the error is a package unit and as such cannot be included in your project. A possible cause of this error is that somehow a Object Pascal unit and a package unit have been given the same name. The compiler is finding the package unit on its search path before it can locate a same-named Object Pascal file. Packages cannot be included in a project by inclusion of the package unit in the uses clause.