DNS resolution problem. You must be able to connect from your machine to all hadoop cluster nodes by host name even though you can do it by IP. In case you are not, simply add mappings of your hadoop cluster nodes to the hosts file of your machine.
Wrong ports. If you don't know what ports you should provide to the h-rider in the connection dialog then go to the hadoop cluster and look for the following parameters in the hbase-site.xml:
hbase.rootdir - the port located in this value is the port you need to connect to the hbase master.
hbase.zookeeper.property.clientPort - this is the port you should use to connect to the ZooKeeper.
The version of the h-rider you have downloaded was compiled with the different version of hbase and/or hadoop. To fix the problem you can do one of the following:
Open manifest file inside the h-rider archive [\META-INF\MANIFEST.MF] - you can use 7-zip application for that purpose. Update hbase/hadoop jar names in this manifest to what you have. After you updated the manifest inside the h-rider archive put your hbase/hadoop jars to the lib folder of the h-rider. The lib folder should be located in the same directory where the h-rider jar is located.
Download the source code and recompile the h-rider with your version of hbase/hadoop. You can change their versions in the POM file.