I found this really helpful, hopefully others looking here will too:

http://www.chrisdanielson.com/2011/05/03/unity3d-file-assetbundles-on-the-iphone/

It is possible to get access to files in the XCode project by first getting Asset.DataPath, and traversing the directory one level to files within the root of the xcode project, eg:

"file://" + Application.dataPath + "/../Packaged_iOS/" + bundleGroupNames[type] + ".unity3d";

Hi, I've a similar problem. This local path seems fine to me. Usually with native iOS you load file with NSURL url = [NSURL urlWithString:@"file://..../Documents/filename"];

var urlFile = "file://" + GetiPhoneDocumentsPath() + "/savedassetbundle.assetbundle";
Debug.Log("---> loading file from: " + urlFile);

downloadFile = new WWW (urlFile);

yield downloadFile;

var assetBundleFile  = downloadFile.assetBundle;
if(assetBundleFile==null)
{
    Debug.Log("---> file not found");
    return;
}

On Unity this doesn't works... does anyone knows why?

It looks like the url you are trying to use is a local path on your computer:

file:///Users/ios/Library/Application Support/iPhone Simulator/4.1/Applications/ABF0D1D0-F88B-41BC-883F-601BC0BC50D1/demo3.app/Data/../AssetBundles/CharacterElementDatabase.assetbundle

This will of course not work on your iPhone.