Problems with importing translations non-unicode utf-8

Hello everybody!

I have a problem with importing of translations. I mean when I want to import file .po with polish translations I receive message:
"39 translation strings were skipped because they contain disallowed HTML”
I want to underline that I have line in .po file with system of coding utf-8. I am sure, that problem is because of polish non-unicode signs, but utf-8 should eliminate this problem.

Is there anybody who knows how to resolve this problem?

Aldim.