Probleme with X11 start on tty4 or tty5 or tty6

[Ludovic watteaux <lebaronlibre@free.fr>]

hi,
My probleme is that X11 don't start sometime on tty7, but on another tty : 4, 
5 or 6.
And then i go on tty3 to do something, i've a message "Init 5 .....
or Init4 disabling for 5 minutes" or something like that.

Any idea ?

Ludovic