Cocos2dx, porting 32bit to 64bit

I have an old source code that I want to publish. Apparently the code is using 32 bit, and now I want to port it to 64 bit. I get this following errors:

ld: warning: directory not found for option '-L/Users/hammyliem/Dropbox/projects-cocos2dx/ZombieSmasher/projects/ZombieSmasher/http://ift.tt/1Ega6NN'
ld: warning: ld: warning: ld: warning: ld: warning: ld: warning: ignoring file /Users/hammyliem/Library/Developer/Xcode/DerivedData/ZombieSmasher-blkanqhhfgudylfmtnqaeimarsin/Build/Intermediates/ArchiveIntermediates/ZombieSmasher/BuildProductsPath/Release-iphoneos/libchipmunk iOS.a, file was built for archive which is not the architecture being linked (arm64): /Users/hammyliem/Library/Developer/Xcode/DerivedData/ZombieSmasher-blkanqhhfgudylfmtnqaeimarsin/Build/Intermediates/ArchiveIntermediates/ZombieSmasher/BuildProductsPath/Release-iphoneos/libchipmunk iOS.aignoring file /Users/hammyliem/Library/Developer/Xcode/DerivedData/ZombieSmasher-blkanqhhfgudylfmtnqaeimarsin/Build/Intermediates/ArchiveIntermediates/ZombieSmasher/BuildProductsPath/Release-iphoneos/libCocosDenshion iOS.a, file was built for archive which is not the architecture being linked (arm64): /Users/hammyliem/Library/Developer/Xcode/DerivedData/ZombieSmasher-blkanqhhfgudylfmtnqaeimarsin/Build/Intermediates/ArchiveIntermediates/ZombieSmasher/BuildProductsPath/Release-iphoneos/libCocosDenshion iOS.aignoring file /Users/hammyliem/Library/Developer/Xcode/DerivedData/ZombieSmasher-blkanqhhfgudylfmtnqaeimarsin/Build/Intermediates/ArchiveIntermediates/ZombieSmasher/BuildProductsPath/Release-iphoneos/libbox2d iOS.a, file was built for archive which is not the architecture being linked (arm64): /Users/hammyliem/Library/Developer/Xcode/DerivedData/ZombieSmasher-blkanqhhfgudylfmtnqaeimarsin/Build/Intermediates/ArchiveIntermediates/ZombieSmasher/BuildProductsPath/Release-iphoneos/libbox2d iOS.aignoring file /Users/hammyliem/Library/Developer/Xcode/DerivedData/ZombieSmasher-blkanqhhfgudylfmtnqaeimarsin/Build/Intermediates/ArchiveIntermediates/ZombieSmasher/BuildProductsPath/Release-iphoneos/libcocos2dx-extensions iOS.a, file was built for archive which is not the architecture being linked (arm64): /Users/hammyliem/Library/Developer/Xcode/DerivedData/ZombieSmasher-blkanqhhfgudylfmtnqaeimarsin/Build/Intermediates/ArchiveIntermediates/ZombieSmasher/BuildProductsPath/Release-iphoneos/libcocos2dx-extensions iOS.aignoring file /Users/hammyliem/Library/Developer/Xcode/DerivedData/ZombieSmasher-blkanqhhfgudylfmtnqaeimarsin/Build/Intermediates/ArchiveIntermediates/ZombieSmasher/BuildProductsPath/Release-iphoneos/libcocos2dx iOS.a, file was built for archive which is not the architecture being linked (arm64): /Users/hammyliem/Library/Developer/Xcode/DerivedData/ZombieSmasher-blkanqhhfgudylfmtnqaeimarsin/Build/Intermediates/ArchiveIntermediates/ZombieSmasher/BuildProductsPath/Release-iphoneos/libcocos2dx iOS.a




Undefined symbols for architecture arm64:
  "cocos2d::Array::createWithCapacity(unsigned int)", referenced from:
      ChooseLevelScene::init() in ChooseLevelScene.o
  "cocos2d::Director::popScene()", referenced from:
      MoreBrain::keyBackClicked()::$_7::operator()() const in MoreBrain.o
  "tinyxml2::XMLAttribute::QueryIntValue(int*) const", referenced from:
      tinyxml2::XMLElement::QueryIntAttribute(char const*, int*) const in XMLAnimation.o
  "tinyxml2::XMLAttribute::QueryFloatValue(float*) const", referenced from:
      tinyxml2::XMLElement::QueryFloatAttribute(char const*, float*) const in XMLAnimation.o
  "cocos2d::Array::containsObject(cocos2d::Object*) const", referenced from:
      XMLAnimation::Layer::Update(float) in XMLAnimation.o
      XMLAnimation::Layer::Restart() in XMLAnimation.o

PLEASE HELP... stuck here for long time... my biggest guess is to change libbox2d iOS.a, and similar files like that, but I also do not know to change them. Thanks.