Hello,
I need some help with the website translation.

I need to know where the words
WORD_or_____ or
WORD_licence license
WORD_upgrade upgrade
WORD_voucher voucher
WORD_item___ Item
WORD_price__ Price

are used. It´s quite a problem,because, for example, with WORD_upgrade I can´t even guess if it is used as a verb or a noun.

I think here?
http://www.lfs.net/?page=shop

Quote from Elevant :

I think here?
http://www.lfs.net/?page=shop

Yes, it's a shop I mean more precisely, where the particular word is used.

This also applies to your language, because you have many cases of nouns. An item title is written in nominative case, but "You have chosen to buy a ..." implies accusative case in Russian. I want to know what string is attached to "to buy a" and make sure that it isn't used in the places where it should be in nominative case.

If someone has already made a translation, I'd be very thankful to hear if there were any problems with cases (Chech, Polish).

Yes, there is

Live for Speed S1 -> S2 upgrade voucher in English so the "upgrade" is an adjective.

In Czech language we have the word "aktualizační" in 4th case (the same as 1st case).