Its solved.
Javi, thanks a lot for your help. after installing a clean ebox it worked perfectly, having roaming profiles (using the latest release of ebox , version .101) disable. Though i did a couple changes to avoid some of the things that i've already commented in this thread.
I created a domain user (always having roaming profiles disable) and i log in the computer(s) where this user is gonna work. I go to My PC (right click), properties, advanced options, user profiles, configuration. And i change the account type to local profile, so every time i log in it's going to load the local profile copy without error messages or without being always a guest. The problem with this is that this user can change its account type, so, not to let him do that, i log in as local administrator, and go to documents and settings, to the user folder, and change the extension of ntuser.dat, being now ntuser.man
Doing this, the account type becomes obligatory so he would not be able to change it.
Hope this is gonna be useful
thanks a lot for your help Javi