Jose: it sounds like you have a slightly old version of the source (the linux version has been changing quickly 
). Run "svn update" from in the root arduino directory, and then, from the build/linux directory, "rm -rf work" and "./make.sh". That should fix the "/dev/dev" problem and the new make.sh script should copy the targets/ directory.
The bootloader issue concerns the baud rate at which it connects to the computer. Older versions of the bootloader (including the one burned on the serial boards at the Madrid workshop) run at 9600 baud. Newer versions (including the one on the pre-assembled USB boards) run at 19200 baud. The baud rate in the bootloader must match the one in the "Tools | Serial port speed" menu or the upload won't work.
Again, thanks for your patience and posts. It's a big help getting the Linux version working (esp. now that my Ubuntu laptop seems to be dead).