The latest and greatest nfs-utils package (part of the linux 2.2.19 update) is missing rquotad. The changelog indicates that the quota package is supposed to have "a version that works with 2.4", but there is no rquotad in the quota package, at least for RedHat 6.2. The end result is that upgrading to the current kernel has disabled NFS quota support.
Fixed in nfs-utils-0.3.1-0.6.x.1 *** This bug has been marked as a duplicate of 36159 ***