If your Flash Builder project is setup in CRX and using a WebDAV client such as NetDrive (http://netdrive.net/) to manage the Gravity source and content, Flash Builder may throw the following error to the Problems view:
unable to load SWC gravity_di_loader_lib.swc
To fix this simply modify the encoding used by the WebDAV client. In NetDrive:
1. Click the Advanced button.
2. Select ‘UTF-8′ from the encoding drop list and choose Ok.
3. Re-build or clean the Flash Builder project.