It did have some minor issues (a patch would make an additional NPC appear), but no game breaking bugs, IIRC.

What do you mean? Like a duplicate npc? Thanks for the heads up.

No, an NPC would not appear in the original game, due to a bug. Patching the game to 1.1 fixes that and makes that NPC available.

I think that Prophet is already an 1.1 version, i'm correct?

prophet patch 1.1 changelog:

Clarifications:
*Pages 18 and 51 in the game book make mention of the Thief's 'Read
Language'power. There is no place in the game where this power may
be used.

Fixes:
*Experience Point Bug is fixed. Players party will no longer gain
Experience points by just walking around the Temple of Set area.

*Crash occurring after party gets 'Judged' in the Royal Burial Hall is
now fixed.

*Anhktepot Bug is fixed. He will no longer freeze-up after quick-
restore is used in the area where he is encountered.

*Double NPCs Bug is now fixed. Parties will no longer encounter two of
the same Ranger/Cleric NPC in the game.

*Spell Book Bug is now fixed. Magic-Users may now select and use the
13th spell for any given level.

*Jackalwere not showing up in game is now fixed.

Just as an FYI to everyone playing Strahd's Possession. Since the GOG version is based upon the CD version of the game, bear in mind that the CD-exclusive enemy, the Living Wall, which is in the caves under Barovia and part of the Fallen Paladin quest is horrifically bugged. To kill it, you MUST rush to confront it head on BEFORE it advances its hands. If its hands advance, collision detection breaks and the enemy cannot be killed. Since killing Living Walls is necessary to open paths in the dungeon it is unique to, this glitch can break that section of the game by sealing paths forever. You must save scum throughout this section to avoid snatching one's hair out because of this bug. Fair warning, folks. This bug is also present on the Masterpiece Collection version (1.2A) and there has never been a fix for it.

Micartu's posted patch is the solution you are looking for. I have played this game for a while, I have the Masterpiece Collection version and I am aware of the game's rather sordid history because of its game-breaking bugs. The Ilvis bug was introduced in the CD version with 1.2. The Masterpiece Collection's 1.2A version patches this out. Essentially, GOG used the wrong patch in its compilation when it released the product. As obscure as the game is, except to D&D fans who remember and love Ravenloft, I doubt that GOG was aware of this. Version 1.2A doesn't eliminate ALL of the bugs. The Jeweler's bug is still there and the Living Wall enemy is bugged beyond belief. However, most of the problems are cleaned up. GOG Support need to update its product with the 1.2A version to avoid folks getting understandably upset when they get to the Ilvis dungeon and the game crashes.

Oh yes, I remember that bug. Luckily it was never game critical for me.

Thanks for the reply. I have it sorted out. I wasn't aware that the master collection had a 1.2A version. I didn't know anyone that owned the collection back in the day so I didn't know about this until now. Most people I knew that had these game had the original copies (CD or otherwise). I just wish I could update my GOG review of Strahd's Possession because it was written mostly out of frustration. I still think, however, that people purchasing this game should be aware of this problem.

Thank you Judas. Much appreciated :)

I am pleased that GOG updated this quickly. My last foray with support did much to undermine my confidence in GOG. This helps to restore lost confidence. Well done. :)

I seem to still be having this problem, which kinda sucks as I was just getting into the game.
And the Dropbox link was removed. :(