[not_so_young_greg]

Thanks Karina again. I managed to get it going with your fixes.
I know it does not insert an Y in test mode - the problem was it did not want to do anything in real mode either. Now it does.
But it still does not want to see any language variables nor include any mail templates. (Mail templates are original and I checked them for errors - seem ok) I managed to do it by hard writing text into mail templates and copying all included files (like mail_header.tpl and others).
Maybe it is because I ran it from the top? But it is suggested in x-cart manual. Maybe it has something to do with permissions?

But it is a bit, well... suprising - it is a fresh installation of 4.5.3 updated to 4.5.4 on Apache server, php 5.2.13. Should work out of the box.
But anyway thanks for your time again.