Me again! New issue with other site. As you can see the interface won't load:
You can try it for yourself. Click here for main page and try to translate it.
I had istalled Translate in MW 1.19 and because of this I've upgraded to 1.21.2. My other wiki (1.21.1) is in the same server and works fine with Translate. I tried various things, like removing all extensions but Translate. Both wikis have pretty much the same configuration.
Any ideas?