Lots have asked about this the last day or so with the latest update, here it is.
You need both installed for this to work. It makes a minimap icon for your errors so they dont get posted on the screen in a huge obstructive box. This way you can see what addon is erroring.
http://www.wowace.com/addons/bugsack/ (http://www.wowace.com/addons/bugsack/)
http://www.wowace.com/addons/bug-grabber/ (http://www.wowace.com/addons/bug-grabber/)