did you try to remove all resource files (*.resx) and re-unzip them from DNN install package and module packages?

WHOA,

Of course I didn't mean Language modules. The module I have messed with is Gallery module. I know it is in development and I have used it on my own risk.

Hi, :). Finally, "with a little help from my friends", I have resolved the problem. The couse was I have also messed with Locales.xml :). I have changed it to following:

<?xml version="1.0" encoding="UTF-8"?>
<root>
  <browserDetection enabled="true" />
  <language name="English (United States)" key="en-US" fallback="" />
  <language name="polski (Polska)" key="pl-PL" fallback="en-US" />
</root>

That one coused problems. I have put insted the following one:

<?xml version="1.0" encoding="UTF-8"?>
<root>
  <language name="English (United States)" key="en-US" fallback="" />
  <browserDetection enabled="false" />
  <language name="Polski (Polska)" key="pl-PL" fallback="en-US" />
  <languageInUrl enabled="false" />
</root>

Now works Language Editor, Time Zone Editor, Languages.

Thanks for help Sebastian.

Best regards

rypki.