I'm getting clicks in the soundtrack when there's screen effects going on, like the magnification on the map.

Is there a fix for this?

This is usually a sign that your processor is not fast enough to handle both the DOS emulation and sound processing in DOSBox. I noticed that GOG set the DOSBox cycles in this game to 80'000 which is quite demanding on the processor. You can try opening "dosboxRayman.conf" in the Rayman directory and make the following changes to the configuration:

Change cycles=80000 to cycles=max (this wil let DOSBox choose the emulation speed, but may cause frequent changes in game speed, so revert this if it does not work well)

Also try making the graphics card as much of the work as possible to relieve your processor:
Change scaler=normal2x to scaler=none (means the pixles are not doubled before passing the image to the output method for scaling, this will make the picture blurrier when scaled to fullscreen though)
Use output=opengl or output=ddraw (use graphics acceleration for drawing and scaling the picture, do this in any case).

If the game still struggles you can try turning off the "Differential Scrolling" in the in-game options or change the video mode to "Vesa" where it will be turned off by default (Make sure to restart the game after changing the video mode to test it out correctly). This is the most demanding, but also the prettiest effect, so only turn this off as a last resort.

Thanks very much. I'll try all that.

I just noticed that GOG used "core=normal" for some reason, you can also try changing that to "core=auto".

Same problem here, i did everything in the 2 posts from Lafazar, still got the clicks, not so many as before but still to many to enjoy the sound of the game. Other solutions?

Im now on a working PC with low specs and a onboard videocard so probably this PC is not powerful enough for DosBox?

My Specs:
Intel(R) Pentium(R) Dual CPU E2160 @ 1.80GHz
Intel(R) G33/G31 Express Chipset Family
2GB RAM
Windows Vista 32-Bit (Yes Vista... sorry guys haha ;) )

Any help please :( ?

Wow, i fixed it in a weird way. I just turned off ''Double Buffering'' and now it runs really smooth without sound problems! Thanks anyway :)!