Lost in loading process

Hi all,

just wanted to scan for thumbnails and to regenerate them because of changes in my themes. So I started the plugin “Regenerate Thumbnails”. Unfortunately, it stays in the status “loading…”.

I tried to reload the plugin’s page in Dashboard with no luck. I de- and reactivated it without success. And I reinstalled it without success.

What good could I do to make this plugin run again?

Cheers, Henning

The page I need help with: [log in to see the link]