Can’t export using NFS

Hi there! I've got a Mac Pro with OS X Server 10.6.7. Since I went in single user mode, NFSd doesn't work. I get in the logs : May 16 10:20:56 wulfgar /sbin/nfsd[41633]: Can't export /Groups: Is a directory (21) May 16 10:20:56 wulfgar /sbin/nfsd[41633]: exports:6: kernel export registration failed: NFS exporting not supported by fstype "hfs" (readdir) I restored from Time Machine. I made /etc/sysctl.conf have the default settings. I tried exporting directories on an other disk. What do I have to do to make it work?