Problem with BuildPipeline.BuildAssetBundle

Hi.

I have an assetBundle created by somebody else, it's in unity3d format.

I load it up using this code:

Code (csharp):

1.  
2.     AssetBundle test = AssetBundle.CreateFromFile("misc_troll_head.unity3d");
3.  
4.     Debug.Log("MainAsset's name: "+test.mainAsset.name);
5.  
6.     Object[] assets = test.LoadAll();
7.     Debug.Log("Found "+assets.Length+" assets inside the bundle. Listing:");
8.     for (int i = 0; i < assets.Length; i++)
9.        Debug.Log (i+" : "+assets[i].name);
10.  

Everything loads fine, here's the debug log:



Now I want to repackage it again.

I do this:

Code (csharp):

1. BuildPipeline.BuildAssetBundle( test.mainAsset, assets, "copy/misc_troll_head.unity3d", BuildAssetBundleOptions.CollectDependencies | BuildAssetBundleOptions.CompleteAssets | BuildAssetBundleOptions.UncompressedAssetBundle, BuildTarget.WebPlayer);

And the file I get is bad. It contains the mainAsset, but it doesn't contain the array of assets.
If I load it up with my first piece of code, here's what I get in debug:


The file is roughly the same size, so the assets must be in there, but they're not loading. Why?