Have a problem here with slitaz 3 persistent usb install..

I boot from the usb and have my /home on it. now almost everytime I boot, this happens:
really always comes message: "cannot execute login command", accompanied by graphical glitches
next: I have to login. if I go as Tux, I get pushed to a grey environment with an mouse-cursor shaped like an x.. I can move this, but can not do anything but push the powerbutton long enough to shutdown.

next: 2nd boot is sometimes ok, and I get back to normal slitaz.
sometimes I need three or four boots to get into slitaz!
does not seem to happen when starting as root.

also sometimes while running slitaz, all buttons and icons on the screen cease to work and I have to press poweroff button to shutdown he computer. (mouse remains moveable and cpu is normal)

any ideas?