I made another DVD replacing the DOS folder file and the GK2.ID at the root and it worked!
Thank you so much Andrew.
I hope to have time soon to re do everything from scratch starting with the new installer as you wish. What happens is that when I´m installing it with the cd´s (and sometimes with the DVD in full installation mode) the progress bar details mark that some files ¨Failed to copy¨so then I need to recopy them manually. Sometimes the files are there so it´s a false call but sometimes they aren´t. It´s always around 4 to 6 files that "fail" to copy. That´s why it´s such a headache.
I suppose it has to do with the sheer amount of files (especially the MOVIES) that the game has. That´s why it even takes like 6-10 minutes to do a Full Installation. It´s not size but quantity of files. So sometimes the installer just can´t copy them, but it will be cool if it lets you know that some files couldn´t copy so you are aware of this. I just know because I was paying close attention to the details of the installation files, in case that this resolved issue with the DOSBox had something to do with it.
At the end, only one files of the reported six was really missing and it was a FMV one. So I just copied it manually when the installation finished and until now it seems to be ok. Anyway, the cds are really old and sometimes they get rusty.
I plan to play this game and finish it, so I plan to report how everything goes. Thank you man, for keeping the adventures alive.