Thanks! Now it works
Only few notes:
1. Use openocd 0.2.0 for installer 1.0.
2. Recompile it if you don't use x86 32 bit cpu (see troubleshooting chapter)
3. If you can't run the script, replace <? with <?php at the beginning
4. If you're root, but he think that you're not, simply comment the 2 lines where there's the check, with /*

So should I use write.e and not write? And could you link me a guide for use sheeva installer to reload uboot? Thanks

I've upgraded uboot by an fat16 usb pen, as this guide says: http://www.cyrius.com/debian/kirkwood/sheevaplug/uboot-upgrade.html
This is the output: http://nopaste.info/49704187d6.html
Everything seemed to be ok, but when I wrote "reset"... It hung up... So I turn it off, and on: no messages, no output, nothing

What the problem could be?

1. 30% used
2. It's compressed. I don't know wich algorithm it uses, but it works sooo well

It was not releated to a mispelled password, but it's a bug occurred after an upgrade of Ubuntu. I've solved it

Connected (with minicom) to my sweet sheeva plug.
Edited the boot loader agruments with:
And then the usual:
Then I've boot it with:

At the comand prompt I've reset root password:

The "reboot" command didn't work, so I restarted it manually. Then, I've write those lines in the bootloader env:
Then I've boot it with:

And it worked

Other resources:
http://plugcomputer.org/plugforum/index.php?topic=110.0
http://computingplugs.com/index.php/Default_software

Actually I'm using a nettop, and I think that I've set a mispelled root password, because I can't login. So, I thinked to put something "init=/bin/sh" (this is the grub-like syntax), mount the fs, and reset the password. The problem is that I don't know how could I say this to uboot. Otherwise, is there a simple way to put debian in the internal nand drive?

Thanks