I'm running into the following issue (below), and I wonder if it has to do with my overall configuration:
- WP 3.4.2 multisite (sub-directory configuration)
On the main site (the site that's in the root folder), I'm able to use the plugin without a glitch (pick the thumbnails I want to edit, select the crop area, advance to Step 2, and resize).
On a second site I created (which is located in a sub-folder), I can't make it to Step 2 (select the thumbnails and crop area, but when I click "Create Thumbnails" I see the loading bar, and then it refreshes Stop 1 instead of moving to Step 2.
Here's the debugging result: http://dpastey.appspot.com//Ujdm/
Each site uses a different theme (not sure if that makes a difference), and the post thumbnail editor plugin is activated individually on each site (rather than "network activated").