Updated this morning – We have plugin success with the latest build!
The “problem children” plugins:
Evens Calendar
NextGEN Gallery
WP-DB Manager
No longer give errors out and can now be managed!
Good work [...]

Going through my site and reactivated the plugins one by one to find the “problem children”. Here is what I found:
The following plugins appear to work with the latest WP 2.7 trunk: they can be activated and managed.
Akismet
All in One Adsense and YPN
All in One SEO Pack
FeedBurner FeedSmith
Google Analytics for WordPress
Google XML Sitemaps
GoStats
Inline Google Maps
K2 [...]