While installing dark forces 2, avira warned me that jk.exe and some other files are trojans... do i have to worry? I think it's just an error on avira's side, right?

I suspect it's another instance of this:

http://www.gog.com/forum/general/beware_rayman_forever_from_gog_contains_infected_files

i.e., a false positive...

Most likely a false positive, as pretty much always. Avira is know for throwing out lots of false positives anyway.

There was a similar thread not so long ago, if you are not as lazy as I am you will find it. :) It should be a false positive. My brother had a similar experience with some other game, I cannot remember which one.

EDIT: Ninja'ed.

Probably a false positive, as usual ! GOG checks its files before to upload them... I hope !

i had too
https://www.youtube.com/watch?v=C4BrcOQH0EA

It's probably another false positive. You can submit the supposedly infected files to <span class="bold">VirusTotal</span> if you want to be sure...

GOG is a worldwide initiative to corrupt the personal computers of nostalgic gamers everywhere. They must be stopped.

I'm pretty sure Disney is installing keyloggers in all of our games to use our credit cards and get some sweet, sweet Flaming Hot Cheetos in bulk.