Unable to read a properties file from DRL file

I am getting this error when my DRL file is attempting to read from a properties file

org.drools.runtime.rule.ConsequenceException: java.lang.NullPointerException
at org.drools.runtime.rule.impl.DefaultConsequenceExceptionHandler.handleException(DefaultConsequenceExceptionHandler.java:23)
at org.drools.common.DefaultAgenda.fireActivation(DefaultAgenda.java:943)
at org.drools.common.DefaultAgenda.fireNextItem(DefaultAgenda.java:885)
at org.drools.common.DefaultAgenda.fireAllRules(DefaultAgenda.java:1086)
at org.drools.common.AbstractWorkingMemory.fireAllRules(AbstractWorkingMemory.java:660)
at org.drools.common.AbstractWorkingMemory.fireAllRules(AbstractWorkingMemory.java:627)
at org.drools.impl.StatefulKnowledgeSessionImpl.fireAllRules(StatefulKnowledgeSessionImpl.java:183)

Any suggestions then please let me know.
Thanks