problem compiling a file

[adele]

Hello, everyone,
Could you please take a look at the
problem I encountered while compiling WebLock.cpp?
I have a class myEnumerator in the same file. When I
compile, I got the following errors. I looked at the
Appendix in your book and couldn't figure out why.
>
I attached all the files needed to compile. If you
need  more info, pls let me know. Thank you.
myEnumerator.cpp: In instantiation of `nsDerivedSafe<nsIComponentManager>':
myEnumerator.cpp:75:   instantiated from here
myEnumerator.cpp:75: base class `nsIComponentManager' has incomplete type
myEnumerator.cpp: In member function `virtual nsresult
   myEnumerator::GetNext(nsISupports**)':
myEnumerator.cpp:78: no matching function for call to `
   nsDerivedSafe<nsIComponentManager>::CreateInstance(const nsCID&, 
int, const
   nsID&, void**)'

Adele
        CXX   = c++ 
 
        CPPFLAGS +=      -fno-rtti       \
         -fno-exceptions         \
         -shared 
         
# Change this to point at your Gecko SDK directory. 
        GECKO_SDK_PATH = /home/adele/gecko-sdk
# GCC only define which allows us to not have to #include mozilla-config 
# in every .cpp file.  If your not using GCC remove this line and add 
# #include "mozilla-config.h" to each of your .cpp files. 
        GECKO_CONFIG_INCLUDE = -include mozilla-config.h 
 
        GECKO_DEFINES  = -DXPCOM_GLUE -DMOZILLA_STRICT_API 
        GECKO_INCLUDES = -I $(GECKO_SDK_PATH)                    \
        -I $(GECKO_SDK_PATH)/xpcom/include      \
        -I $(GECKO_SDK_PATH)/nspr/include       \
        -I $(GECKO_SDK_PATH)/string/include     \
        -I $(GECKO_SDK_PATH)/embedstring/include \
        -I .

        GECKO_LDFLAGS =  -L $(GECKO_SDK_PATH)/xpcom/bin -lxpcomglue \
        -L $(GECKO_SDK_PATH)/nspr/bin -lnspr4      \
        -L $(GECKO_SDK_PATH)/nspr/bin -lplds4      \
        -L $(GECKO_SDK_PATH)/embedstring/bin/ -lembedstring 
 
build: 
        $(CXX) -c $(GECKO_CONFIG_INCLUDE) $(GECKO_DEFINES) $(GECKO_INCLUDES) 
$(GECKO_LDFLAGS) $(CPPFLAGS) $(CXXFLAGS) myEnumerator.cpp
 
clean: 


#include "nsIGenericFactory.h"

#include "nsCOMPtr.h"
#include "nsXPCOM.h"
#include "nsIServiceManager.h"
#include "nsICategoryManager.h"

#include "nsIObserver.h"

#include "nsEmbedString.h"
#include "nsMemory.h"

#include "nsXPCOMCID.h" 
#include "nsISupportsPrimitives.h"
#include <stdlib.h>

static NS_DEFINE_CID(kSupportsCStringCID, NS_SUPPORTS_CSTRING_CID); 


// a simple link list. 
struct urlNode 
{ 
    char* urlString; 
    struct urlNode* next; 
};  

class myEnumerator : public nsISimpleEnumerator 
{ 
public: 
    NS_DECL_ISUPPORTS 
    NS_DECL_NSISIMPLEENUMERATOR 
 
    myEnumerator(urlNode* node) { mNode = node; } 
    virtual ~myEnumerator(void) {} 
 
protected: 
    urlNode* mNode; 
    nsCOMPtr<nsIComponentManager> mCompMgr; 
}; 

NS_IMETHODIMP 
myEnumerator::HasMoreElements(PRBool* aResult) 
{ 
    if (!aResult) 
        return NS_ERROR_NULL_POINTER; 
 
    if (!mNode) { 
        *aResult = PR_FALSE; 
        return NS_OK; 
    } 
 
    *aResult = PR_TRUE; 
    return NS_OK; 
} 

NS_IMETHODIMP 
myEnumerator::GetNext(nsISupports** aResult) 
{ 
    if (! aResult) 
        return NS_ERROR_NULL_POINTER; 
 
    *aResult = nsnull; 
 
    if (!mNode) 
        return NS_ERROR_FAILURE; 
 
    if (!mCompMgr) { 
        NS_GetComponentManager(getter_AddRefs(mCompMgr)); 
        if (!mCompMgr)  
            return NS_ERROR_UNEXPECTED; 
    } 
 
 
    nsISupportsCString* stringSupports; 
    mCompMgr->CreateInstance(kSupportsCStringCID,  
                             nsnull,  
                             NS_GET_IID(nsISupportsCString),  
                             (void**)&stringSupports); 
    if (!stringSupports) 
        return NS_ERROR_UNEXPECTED; 
 
     
    nsEmbedCString str(mNode->urlString); 
    stringSupports->SetData(str); 
     
    *aResult = stringSupports; // addref'ed above. 
 
    mNode = mNode->next; 
 
    return NS_OK; 
}