[wp-testers] Invalid argument in widgets.php on import

[Food Dude]

Using 2.5-beta 1 on localhost. Initial setup as a new installation worked
fine. Imported WP 2.3.3 DB from another site through php myadmin. After
import, WP goes to "need to upgrade" page, but top of page throws error:

Warning: array_keys() [function.array-keys]: The first argument should be an
array in C:\wamp\www\pfd\wp-includes\widgets.php on line 656

Warning: Invalid argument supplied for foreach() in
C:\wamp\www\pfd\wp-includes\widgets.php on line 656

Upgrade proceeded ok, but after upgrade every page gives this error, both in
admin and on site. All plugins are disabled,  all widgets removed. Default
theme selected. Just for kicks, I tried it a second time with the same
error.