Ubuntu Problems

Partially got Ubuntu installed on my Macbook after fighting with apt-get for an hour. Every-time I tried to do an apt-get update or install it complained about there being no packages to install.It  looks like apt threw a wobbly and #'d out the repositories in /apt.conf during the install before I could setup the correct proxy server address. A quick trip down etc lane with nano in tow and the problem was resolved. Yayh for me. But still, sda4 is still unbootable by Bootkamp as I haven't figured out how to write the .cdr file to a cd yet. I have only tried this in windows so I don't know if there is some special magic UNIX command to do that. I'll Google that as soon as our ADSL gets connected.