The problems come from the modutils package and the PATH. When I installed the 'buggy' package, I saw a message about the line PATH in the conf.modules file. The syntaxe of the line has changed from PATH[fs]=/lib/module/2.2.12 to PATH[fs]=/lib/module/2.2.12/fs (I'm not sure of the correct syntaxe, but we have to add the name of the 'section' at the end).
What was wrong is that the default paths have not been changed. To solve the problem, we just have to add the correct default paths in /etc/modutils/path, do update-modules, depmod -a, and all is good.
