When I include "catlist" in the administration section the result for the index page is a blank page (even in debug mode) no error just blank.
I can acceed to the category by direct url : mysite/coppermine/index-1.html for exemple.
So for the moment, I have created an html menu with all the statics url leading to the category.
But it's not a pleasant solution. :-[
I must say that I have this problem for a long time from older version of coppermine but upgrades to version 1.4.9 does not change anything.
I would appreciate an advise
disable sef-url plugin and try again