Have seen this problem reported on other sites (including ubisoft forum) and have also encountered this on one of my systems. Certain levels will have missing objects in them which you will bump in to (or will kill you) and you will not be able to see them.
One of the posts found on Ubisoft's forum suggests that this may be due to an unsupported video card.... the one I am having trouble with is an NVidia Quadro fx1500 (my machine with a GeForce gt560 does not have this problem)
So I guess my question is, is there a list of supported cards or does anyone know of a setting that can be changed to avoid this?

I ran into that issue only once with the retail game (I have a HD 4850 1gb). Don't know what caused it.

I did have some other problems for which I can provide some work-arounds.

I have a 5:4 screen and fullscreen mode would give me black bars, but not scale correctly resulting in a large part of the top and bottom of the game being obscured while it would be visible if I could run in widescreen mode natively. Running it in windowed mode so that it can run in a widescreen resolution 'solved' that issue.

Other than that I had a hand-full of times where I would return to the world map unable to move, totally ruining the save-file. I ended up manually backing up my save-files in order to prevent losing progress (documents/my games/rayman origins).

All issues aside, it was a great game and I might buy it here again just to get the soundtrack.

I've bought the game today and didn't experience any issue at all. Thanks for the heads up though, let's hope the game runs smoothly.