xp sees vista but cant open shared folders

I just set up my network running vista home premium on one machine, xp home v2002 sp 3 on the other. I can acces the xp file from the vista, but not the other way around. I can see the folder on the xp, but I get the error " \(folder)\ not accessible. You might not have permission to use this network resource. Contact the administrator of this server to find out if you have access permissions."
Network discovery, file sharing, public folder sharing, media sharing are all on. What am I missing??
I have also found that I can access the files in the public folders but not the ones I manually set up sharing on...
I don't want to have to paste everything I want to share into the public folders. Please HELP!!
thanx

you have password set for the login on vista right if not set one
then when you click on the folders to acccess youll be prompted for the user and pass use the one for the vista machine

Thanks, I set up a login for vista machine, the log in box comes up when I click on the folder but I still get the same message when I log on.