It's perfect adi619 !!!!
Thanks a lot, the problem was in the mode
I selected high speed mode, that was the problem.
For mice and keyboards we should select low speed mode.
Now everything is ok
These are the steps to connect a mouse or a keyboard to the n900

Instalaltions
1- Install power kernel
2- Install h-e-n
--------------------------------------------------------------------
To Execute

1.. Start h-e-n

2. Connect the data cable to the n900

3. Connect the mouse to the Cable

4. In h-e-n select low speed hostmode

5. Click v boost on

6. Click enumarate

7.wait a minute and u'll get a message "connected to OM"



Thanks to adi619 for his help by Private Message
And thanks to the community