I can't read the language indicator on the taskbar because it's white on light blue background.

Normaly it should be white on dark blue.

Never encountered this. Sounds a bit like 4-bit color mode, but even with that it'd normally look okay. Can you show a screenshot?

Ok, some hints,

I notice that it comes from my customized desktop color sheme (appearance). When I revert to a standard color sheme, the language indicator turns dark blue again after reboot.

So, internat.exe picks its color from the desktop color sheme applied. Therefore I re-edited my personalised color sheme changing every item where this color appeared. I found it on one place: On "active title text". I changed this color to dark blue. rebooted, and... the light blue color was back!

Eventhought there is NO white blue color in the new sheme!

I realy wonder where it finds this color.

You could try checking a disassembly of the file. Not much code in there.