First of all: We have nothing against Ubuntu as Linux distribution.
But unfortunately there are many Ubuntu (sometimes on Debian or currently Opensuse 11, too) specific problems, which do not happen on other distributions/operating systems.
In order to make sure that a problem is really aMule related and does not only happen on a specific distribution, we ask you to use a 
self-compiled wxGTK installation and possibly a self-compiled crypto++-library as well when 
reporting problems.
We will offer 
no support for problems related to distribution packages (aMule, wxGTK, crypto++) anymore. Please report such bugs on the bug tracker facilities of your distribution. We have lamentably only limited developer time and would like to spend it to improve aMule to be as good as we can, not investigating errors which are not caused by aMule itself.
See also the 
related Wiki article.
Thank you for you understanding.