Long story short, there is a bug in Path of Destiny for me, at least.
The gift of the Lady of the Lake simply does not want to materialize, no matter how long I meditate or how many times I come back. I am officially fed up (I've tried for the past five hours to get it to work).

Is there someone who can fix my save file or can someone import a save file right after the Dagon is beaten and the sword given so that I may continue?

If I left anything important out, please tell me, I'll be sure to add it in...

You can use ScripterRon's marvelous Saved Game Editor to add the sword to your inventory. You can find it here: http://en.thewitcher.com/forum/index.php?/topic/7328-tw1tool-save-game-editor/

The Genie Wish Mod would also allow you to get the sword, but that might not be as satisfying as altering your saved game.

You did get the cutscene where the Lady of the Lake knights you and presents you with the sword? It's one of the coolest cutscenes in the game, so I hope you saw that. And if you DIDN'T see it, then you're not supposed to have the sword yet.

The problem is the fact that I get the sword (and yes, the cutscenes is awesome) and Berengar never materializes, so I cannot continue with the story, because as a result, Alvin never gets kidnapped nor the White Rayla appears... (Sorry, should have been more clear, and thank you for the reply)

Bump...

I don't have a surefire solution for this, but there was a similar discussion a while back that might help. Check here:

http://www.gog.com/forum/the_witcher/q_cant_finish_chapter_iv/page1

Once I get back to my computer, I'll try both possible solutions again...

I think I figured out the problem:

When Heat of Day is completed first, and you complete Ripples the way the Lady of Lake wants to, you only get the sword (which is the prize for completing Heat of Day, and not Ripples)...
And since the Lady of the Lake dissapears after giving the sword, Ripples is never completed...

Ergo, you are stuck...

Yay... :/

I have the same problem here

Alvin - Stops at "A Gift" phase and is active, whenever I track the quest, it directs me to the Dagon's altar.
The Path of Destiny - Stops at "Berengar should pay" or something like that

Read the guide and there are few things that aren't going as they're supposed to, which are :
- I already completed all secondary quests at the point when I defeated Dagon, talked to the lady and obtained Aerondight. The guide says something about meeting Berengar at the boat, but it's not happening. So no Berengar, no fight with him after the Aerondight or anything.
- Went back to the lakeside and Alvin doesn't say anything.
- Never met White Rayla.

Have you found a way out for this? If you have, I would truly appreciate it if you share... This one starts to annoy me, since I don't have the closest save file to the recent quests. :)

Regards