Hadoop Configuration Error
I think you're running into HADOOP-2851. This "error" can safely be ignored.
Apparently, Configuration's constructor logs an exception to the debug log, despite no exception actually being thrown. Why? Your guess is as good as mine. But the issue is resolved in their project as won't fix. "It's a feature, not a bug."
public Configuration(boolean loadDefaults) { if (LOG.isDebugEnabled()) { LOG.debug(StringUtils.stringifyException(new IOException("config()"))); } // ...}