And why when i mounted the file on my computer, the /dev wasn't empty? i had closed the chroot on the tablet. And also when i was trying to copy the files "mem" and "kmem" on my desktop linux, the system was crashing.

I just thought i'd mention that for anyone 'afraid' of resizing the image in situ with resize2fs, you can also do it by plugging the tablet into any computer system, backing the image up onto that machine, and using that system's resize2fs to resize. (There are also Windows apps that can resize ext3 images.) It also helps to fsck repeatedly. (Joke away...) - DR

Resizing on linux system using card reader works for me well. Thank you.

i also had lack of free space on my ext2 image...
since my os2008 resides on the internal mmc (mine is a n800), which is ext2 formatted _already_ and has more or less a couple of gbytes of free space, i decided to copy the entire content of the image inside the /debian folder directly.
this way i solved any issue related to lack of free space, my /debian environment soddenly became "dynamic" (it takes the exactly amount of disk space it needs), and it is much faster! (no need to mount the image as a loopback device, and no need to load other kernel modules to handle it!)
today i installed "qcad", a true cad running on my tablet... this chrooted debian trick turned my n800 in a BEAST!