I realized that the problem is due to DOCman Ultimate Download Module 1.5 : http://www.alfystudio.com/download/file/109.html

I don't have time to investigate more for the moment but at least you know that there are troubles with sh404&Ultimate Download Module 1.5!

Thank you.

May be in future when I will have free time, I will check where problem

I found the solution!!!!!!
That's a setting in sh404 config>plugins>docman

If you want to include a "root" word in your docman URL, you have to tick the box (first parameter)

THEN go to sh404 config>plugins>per component
in the last column, write the word you need in your url!

I had problems with Xmap and the module ultimate download for docman, the links were completly fucked but now it's fully working