I'm not sure about downloading files with spaces. I haven't had any success with q3dirtrav yet. You might try replacing the space with %20 in each space.
For example:
/download file%20name.txt
I think that most q3 stuff has underscores in the file names instead of spaces.
For your other question check out this:
http://www.youtube.com/watch?v=z1KfnYB8RIo
http://aluigi.altervista.org/adv/q3cbof-adv.txt
lol...now i'll let Luigi come and explain it all :P