http://img99.imageshack.us/img99/457/768531wj8.jpg
if I change something in pl.txt

why do I have this error ?
and how to open files *.qm ?

You have this error because your text editor adds invisible characters at the start of the file pl.txt, you may see them in this error message.
.qm file are not supposed to be opened, you should edit .ts files instead (which could be found in project's source files). You may use Qt4's Linguist for that purpose, and Qt4's lrelease to produce .qm files out of them.

Sorry, but what are you talking about, i see lines you pasted correctly. I translate this game into Polish so if you want to correct anything please let me know, ok?

Ok, I talked with unC0Rr. It was my mistake. I'm sorry.