Should be ok. On the dbox, go to /var/bin/emu or where ever the emu file is stored.
Copy it to your PC. Then connect to your dreambox and go to where the emu file is stored, usually same location.
Copy the file there and overwrite the file that's there. CHMOD 755 and that's it.
Make sure you are using another emu first, i.e. of you are changing the mgcamd file, switch to evocamd first.