I don´t know which version of RBBB do you have, but searching quicly on RBBB site I found many docs that can help you:http://moderndevice.com/Docs/RBBBv1.5.revB.pdfhttp://moderndevice.com/Docs/RBBBv1.6.revB2.pdfhttp://moderndevice.com/Docs/RBBB_Instructions_04.pdf
I´m not sure, but it seems that if you didn´t make the autoreset hack on your board, you must press the reset button when uploading a sketch.
I´m sure there are people here that can help you with more than this (other RBBB users, or people with more knowledge), but I saw a forum link on moderndevice site:http://moderndevice.com/phpBB3/
If you could not find real help here, or the answer is not in doc files, perhaps you can get help in that forum.
P.S.: just a comment: you wrote "pin 13 of atmega168..." but the correct is pin13 of RBBB board (or pin13 of Arduino Board). The pin13 of RBBB is equal to pin19 of the atmega168.