I have updated my Ubuntu box to 11.10 and then Eclipse also have been updated to 3.7.0 Indigo with CDT 8.0.1
Then the following problem occurs:
When you create a C++ project (in my case from existing code) you have to set the 'Toolchain for Indexer Settings' to the compiler you use ('GNU Autotools Toolchains' in my case). After this 'Path and Symbols' will show the correct path to the include files of your compiler. The bugs will disappear. This setting was useful only during creating the project, setting it later did not help.
In indigo 3.7.2 version (and up may be) your changes can be effect after reindexing. Eclipse ask for "reindexing". Lower versions can require a manual reindexing header tags etc.