Displaying messages are not editing

Hi,

I have a great issue with the messages shown after clicking the Submit button.
I am from Poland and need them to be in Polish – I found the code in es-register.php, translated messages on my own, then checked it on my PC and it worked. BUT it does not work on any other device. I asked friends, checked it on my mobile phone – it is still in english. As if the file did not upload and was ‘available’ only on my PC. I tried restarting WinSCP I am using, restarting my PC – still no effects.
I have no idea how to solve that matter.