Well, this is a problem I've been having a long time ago, with CVS versions and the new 2.1.0.
More or less, it is related to upload/download speed, and to conexions. The problem, amule colapses internet conexions, so I can rarely surf the web when amule has been running for a time, not a long time. I changed everything i could to avoid it (max conexions, ports, etc), but nothing really worked. I know I own a router a bit bad (a Xavi model), what I kwnow it has problems with a huge number off conexions, but I downloaded an upgrade that was supposed to fix that, and it was so. Now, the problem persists, but now it only affects to my Gentoo machine, conected via ethernet to the router. Two more PCs with WinXP installed can surf more or less good via wireless. So, i start believing I had something wrong configured in my machine. I reconfigured kernel, switching diferent options of my net card, but nothing really fix something.
But the more strange thing happend me today. When the amule was more or less acceptable (slow, but acceptable), I had to burn a Music CD, and what was my surprise when cdrecord/k3b give me an error about not being able to tho that tastk. I tried more times, and nothing, but then, I closed amule, and... oh! I could burn the CD. So the only thing I really know is that I have or don't have something than doesn't works well on my system. Anyone has or have had this problem or know how to solve it?

? It is something very strange.
I use kernel 2.6.14, wxGTK 2.6.2 with GTK2, amule 2.1.0
Thanks you very much and sorry if my English is not as good as it is supossed to.