The issue seems to be a miss-detection of the entity type in the code, incorrectly assigning flickr and youtube types to the default “list” type. I have hacked together a quick patch which seems to be working for me (but crucially doesn’t fix the underlying problem).
Normally I wouldn’t post this sort of thing here, however it would appear that Evan is no longer maintaining the plugin and has turned off comments. Hopefully, if you are having the same issue as I was, this might be useful to you.
» friendfeed-activity-widget-mp.zip – My modification of 1.1.3
Image from Friendfeed.com