I am using the distfork plugin intensively. In the Jenkins log file there are many warnings like this:

Jun 25, 2014 1:36:12 AM hudson.ExpressionFactory2$JexlExpression evaluate
WARNING: Caught exception evaluating: exeparent.url in /. Reason: java.lang.reflect.InvocationTargetException
java.lang.reflect.InvocationTargetException
at sun.reflect.GeneratedMethodAccessor336.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.apache.commons.jexl.util.PropertyExecutor.execute(PropertyExecutor.java:125)
.....
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:662)
Caused by: java.lang.UnsupportedOperationException
at hudson.plugins.distfork.DistForkTask.getUrl(DistForkTask.java:102)
... 191 more

These are only warnings, but they cause huge jenkins log files.

How can these warnings be avoided?