I've released a few updates to AMF Explorer over the last week or so. Improvements include support for small messages, better formatting, and better error messages. You can get the latest from the AMO site.
Unfortunately automatic updates are not enabled because AMF Explorer has yet to go public. If you are using AMF Explorer please consider taking the time to register and review the add-on on the AMO site as this will help with the AMO review process. Once the add-on is public it will be easier to find and install as it will not be marked as experimental and automatic updates will be enabled. Thanks!