Connecting to MacBook on same wireless network

I would like to connect to my friend's MacBook to obtain some files he has in his shared folder. I have tried connecting directly to his shared folder and it tells me that I need some kind of password to get access to it. He has told me that he has not set up a password for this type of activity.

He has personal file sharing and windows sharing turned on. I can't figure out what to do. I have a G4 Powerbook.

If your getting blocked it would be easier to copy the data to and external hard drive, then you can just copy it to your system. I usually dump backup folders and files to a .Mac account or leave a copy on the Airport Extremes network external.