NullPointerException with zookeepers getZookeeperClusterKey

Hi,

when connecting to HBase, the following message occurs:

 java.lang.NullPointerException
    at java.lang.StringBuilder.<init>(StringBuilder.java:92)
    at org.apache.hadoop.hbase.zookeeper.ZooKeeperWrapper.getZookeeperClusterKey(ZooKeeperWrapper.java:956)

There seems to be a problem in the configuration. I'm not using an xml-file for configuration, but do this in my code. For the record, this is the configuration part of my code:

usersTable = new HTable(config, "users");
config.set("hbase.zookeeper.quorum", "student-serv002.test");

I'm running this from an OSGi application using Spring DM.

Thanks in advance!