It doesn't sounds "normal".
I'm not sure if ResourceHacker is a good tool for the translation... a few times, I have encountered some problems with files editted by ResourceHacker (the executable image was corrupted). I'm not talking about avast! right now, just in general...
If you are interested, I can send you the original RC files - but you wouldn't be able to open them in ResourceHacker, you'd need some other tool.
As for your question... it seems ResourceHacker doesn't know some constant; did you put LANG_SLOVENIAN there, or just SLOVENIAN, which wouldn't be correct?