Thisfatal: reference is not a tree: b51de15acb37d72719b03314771e4caa04e57a33was quite annoying.

I have made some initial fixes that will at least get you past getting all the proper submodules:
3351040

There is a multi-step process in order to make this work (detached HEAD) with the latest for tag “release-1.1-RC0”

1) Under the root directory of this repository,edit the “.gitmodules” with the following diffs:

diff --git a/.gitmodules b/.gitmodules
index 70efbcf..e61c729 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -1,12 +1,12 @@
 [submodule "CocosBuilder/libs/cocos2d-iphone"]
        path = CocosBuilder/libs/cocos2d-iphone
-       url = https://github.com/cocos2d/cocos2d-iphone.git
+       url = git://github.com/cocos2d/cocos2d-iphone-classic.git
 [submodule "CocosBuilder/libs/ssziparchive"]
        path = CocosBuilder/libs/ssziparchive
-       url = https://github.com/vlidholt/ssziparchive
+       url = git://github.com/vlidholt/ssziparchive
 [submodule "CocosBuilder/libs/Fragaria"]
        path = CocosBuilder/libs/Fragaria
-       url = https://github.com/vlidholt/Fragaria.git
+       url = git://github.com/vlidholt/Fragaria.git
 [submodule "Examples/CocosBuilderExample/libs/CCBReader"]
        path = Examples/CocosBuilderExample/libs/CCBReader
        url = git://github.com/cocos2d/CCBReader.git

2)$ cd CocosBuilder/libs/cocos2d-iphone
3)$ git checkout 9bd04c2286e32a8bc5ba90f85de1170b91d86d1f