I will answer myself after 24 hours trying to solve the problem...
First download dcraw.c from the author's webpage --> http://www.cybercom.net/~dcoffin/dcraw/dcraw.c
I recommend to save it somewhere inside your gallery installation, just in case there are access problems. I set it on a bin folder inside my gallery2 installation.
Once the file is copied, just login from a terminal, navigate to the file and enter gcc -o dcraw -O4 dcraw.c -lm -DNO_JPEG -DNO_LCMS
Now point to the newly created dcraw file in your plugin area at the gallery2 site admin. Welcome to RAW support!