Same here, managed to get it to work using the FC1 nfs-utils RPM.
http://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=123017 claims that it is because of the patches that were applied by RH to the nfs-utils. Probably the nfs-utils tar ball from nfs.sf.net will work too.
Does anyone know how to get a nfsd using the vanilla kernel to work with the nfs-utils from FC2 ? Don't like the idea of using FC1 nfs-utils
Serge