Xcode 4.2 warnings with iPhone example code (on Mac 10.7)

I’m still finding my way round oF but have successfully managed to get the iPhone examples running in Xcode, the simulator and on my iOS devices. However, whenever I build I get a series of compilation warnings.

The first warning I get is the Xcode project (before build) saying the project needs to be upgraded. Would anyone recommended I do this?

The next set of warnings appear after building any of the examples, such as:

  
  
warning: 'virtual void ofBaseDraws::draw(const ofPoint&)' was hidden  
warning: 'virtual void ofBaseDraws::draw(const ofRectangle&)' was hidden  
warning: 'virtual void ofBaseDraws::draw(const ofPoint&)' was hidden  
  

and so on, all reported as “LLVM GCC 4.2 Warning”:

Any advice on how to remove these warnings?
Thanks loads,
Paul.