MySQL Cluster 6.3.28 has now been witdrawn, please use 6.3.28a instead: http://www.clusterdb.com/mysql-cluster/mysql-cluster-6-3-28a-source-release-now-available-replaces-6-3-28/
The source version for MySQL Cluster 6.3.28 has now been made available at ftp://ftp.mysql.com/pub/mysql/download/cluster_telco/mysql-5.1.39-ndb-6.3.28/
You can either wait for the binaries to be released or if you’re in a rush then you can find instructions on building the binaries for yourself in the earlier article: “MySQL Cluster 7.0.7 source released“.
A description of all of the changes (fixes) that have gone into MySQL Cluster 6.3.28 (compared to 6.3.27) can be found in the MySQL Cluster Cluster 6.3. 28 ChangeLog.