DataNode无法在Hadoop中启动

I trying setup Hadoop install on Ubuntu 11.04 and Java 6 sun. I was working with hadoop 0.20.203 rc1 build. I am repeatedly running into an issue on Ubuntu 11.04 with java-6-sun. When I try to start the hadoop, the datanode doesn't start due to "Cannot access storage".I trying setup Hadoop install on Ubuntu 11.04 a