Xcode runtime error: ".objc_class_name_CContext", referenced from:

I'm getting this error in Xcode while developing an app for iPhone , what is this error related to, ... what should i do to clear this error? Here CContext and CManager are interface which implement there own protocols.And TestManagerAppDelegate is the interface where i'm creating the object for CContext and CManager and i want to call the methods using there own objects.

ERROR:

".objc_class_name_CContext", referenced from:
".objc_class_name_CManager", referenced from:
collect2:id retirned 1 exit status
literal-pointer@_OBJC@_cls_refs@CContext in TestManagerAppDelegate.o
li开发者_开发知识库teral-pointer@_OBJC@_cls_refs@Cmanager in TestManagerAppDelegate.o
symbol(s) not found

It looks like the files that contain the implementations for the CContext and CManager classes (probably CContext.m and CManager.m) were not included in your Xcode project.