The thing I've learned is that each purchase works for one account only. In the case of the russian cd key etc, the license provided is some kind of authentication key made from the MD5 hash of the real account. The creator of the program creates this license for you. If you run the program without the proper license for your account, it won't work. If we could somehow figure out the creator makes that license key from the MD5 hash of accounts, we could probably be able to run 5.0, and perhaps later versions as well.
That's what I think anyways, I'm not really experienced with this type of stuff, so take this with a bucket of salt.
I have one question, however: If the reset trial works on 5.0, then that would be perfect for me, unfortunately I registered the program with the russian CD key, and it doesn't want to go away whatever I do. I tried emiron's Trial-Reset program and deleted all files, but to no avail. Anyone have any ideas?
And for those who get license error when running the program, remember to move "license.ini" to L2C's root folder (the license.ini file that comes with the cd key)