RuntimeException with log4j

[adastidar]

I am using this layout in Wowza to enable JSON logging. In certain cases, the layout encounters a runtime exception and throws the following to stdout/stderr:

java.lang.RuntimeException: java.lang.NoSuchMethodException: com.wowza.wms.stream.file.PlaylistNode.isO()
        at net.minidev.json.JSONValue.writeJSONString(JSONValue.java:625)
        at net.minidev.json.JSONObject.writeJSONKV(JSONObject.java:102)
        at net.minidev.json.JSONObject.writeJSON(JSONObject.java:169)
        at net.minidev.json.JSONValue.writeJSONString(JSONValue.java:491)
        at net.minidev.json.JSONObject.writeJSONKV(JSONObject.java:102)
        at net.minidev.json.JSONObject.writeJSON(JSONObject.java:169)
        at net.minidev.json.JSONObject.toJSONString(JSONObject.java:72)
        at net.minidev.json.JSONObject.toString(JSONObject.java:261)
        at net.logstash.log4j.JSONEventLayoutV1.format(JSONEventLayoutV1.java:137)
        at org.apache.log4j.WriterAppender.subAppend(WriterAppender.java:310)
        at org.apache.log4j.RollingFileAppender.subAppend(RollingFileAppender.java:276)
        at org.apache.log4j.WriterAppender.append(WriterAppender.java:162)
        at org.apache.log4j.AppenderSkeleton.doAppend(AppenderSkeleton.java:251)
        at org.apache.log4j.helpers.AppenderAttachableImpl.appendLoopOnAppenders(AppenderAttachableImpl.java:66)
        at org.apache.log4j.Category.callAppenders(Category.java:206)
        at org.apache.log4j.Category.forcedLog(Category.java:391)
        at org.apache.log4j.Category.log(Category.java:838)
        at com.wowza.wms.logging.WMSLogger.log(WMSLogger.java:203)
        at com.wowza.wms.logging.WMSLogger.info(WMSLogger.java:258)
        at com.wowza.wms.stream.file.PlaylistPlayer.play(PlaylistPlayer.java:1161)
        at com.wowza.wms.stream.file.MediaStreamFilePlay.play(MediaStreamFilePlay.java:111)
        at com.wowza.wms.response.ResponseStreams.output(ResponseStreams.java:51)
        at com.wowza.wms.request.RTMPRequestAdapter.service(RTMPRequestAdapter.java:671)
        at com.wowza.wms.server.ServerHandler.a(ServerHandler.java:706)
        at com.wowza.wms.server.ServerHandler.a(ServerHandler.java:415)
        at com.wowza.wms.server.ServerHandler.sessionIdle(ServerHandler.java:585)
        at com.wowza.wms.server.ServerHandlerThreadedSession.run(ServerHandlerThreadedSession.java:111)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
        at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.NoSuchMethodException: com.wowza.wms.stream.file.PlaylistNode.isO()
        at java.lang.Class.getDeclaredMethod(Unknown Source)
        at net.minidev.json.JSONValue.writeJSONString(JSONValue.java:610)
        ... 29 more

Any ideas on what can be done next?