That's an error message raised by CW:
Error   : object 'CSemModel::NotifyObserverL(MSemModelObserver::TModelEvent)'
csemmodel.cpp line 253
Error   : Compile failed
And that's the equivalent gcc error message:
Error   : redefinition of `void CSemModel::NotifyObserverL(enum MSemModelObserver::TModelEvent)'
CSEMMODEL.cpp line 253
Error   : `void CSemModel::NotifyObserverL(enum MSemModelObserver::TModelEvent)' previously defined here
CSEMMODEL.cpp line 209
Error   : Compile failed
gna CW for Symbian OS is not a C++ compiler, it's a disease.