I18N Gallery

[mvlcek]

Experiencing problems which haven't occurred before...

When I try to add image to new gallery, the pop-up window is blank...
(http://whatever.url.com/plugins/i18n_gal...=160&h=120)

If I remove files from uploads folder root, I can then see folder I've created in file browser window.
I can move into that folder in the file browser window, but only if it contains no files. If there are files in it, the browser window then stays blank.

Latest edition of i18n gallery 1.9.2, GS3.1 (combination has worked spectacularly well before, with the same webhost...)

Tried to add sitewide cookies to config - no help.
Checked root url in site settings - is ok, no help.
I disabled all other plugins - no help.
Chmod data folder 0777 - no help.
Check file ownership - no help.

Anything other to try?
I'm all lost.

Any specific file that causes the problem?