"There are no shares available or you are not allowed access them..."

I'm admittedly a bit rusty, last time I set up a Mac OS server was 10.4. I'm having a huge problem setting up basic file sharing and it's driving me nuts!

For testing and trouble shooting I've set up a single share, a single user and added that user to a single group. I enabled all services for the user. I then set the POSIX permissions on the share to read and write for the user and the group. I also tried additional ACL permissions to full control. No matter what I do I still get "There are no shares available or you are not allowed to access them on the server". I can log on any admin account with no problems, but I can't get standard accounts to connect! I've tried stopping and starting AFP service with no change. I've re-read all the AFP and permissions sections of the admin guides and the server essentials book. From what I can tell this should all be working. What am I missing?

Thanks in advance