Office Connector throwing NPE with some powerpoint files

2014-07-14 14:19:20,136 ERROR [DefaultSlideCacheManager:thread-2] [com.benryan.conversion.AbstractSlideConversionTask] call problem while converting scrum basics.pptx
 -- referer: http://localhost:8080/confluence/display/ds/Welcome+to+Confluence | url: /confluence/plugins/servlet/pptslide | userName: admin
java.lang.NullPointerException
	at com.benryan.pptx.record.XMLParagraphStyle.<init>(XMLParagraphStyle.java:45)
	at com.benryan.pptx.record.AbstractSlideModel.loadStyle(AbstractSlideModel.java:258)
	at com.benryan.pptx.record.AbstractSlideModel.loadListLevels(AbstractSlideModel.java:210)
	at com.benryan.pptx.record.SlideMaster.<init>(SlideMaster.java:49)
	at com.benryan.pptx.XMLSlideShow.getXMLSlide(XMLSlideShow.java:224)
	at com.benryan.pptx.XMLSlideShow.getSlide(XMLSlideShow.java:290)
	at com.benryan.ppt.PptRenderer.render(PptRenderer.java:78)
	at com.benryan.conversion.PPtDocumentConversionTask.convertFile(PPtDocumentConversionTask.java:56)
	at com.benryan.conversion.PPtDocumentConversionTask.convertFile(PPtDocumentConversionTask.java:27)
	at com.benryan.conversion.AbstractSlideConversionTask.call(AbstractSlideConversionTask.java:50)
	at java.util.concurrent.FutureTask.run(FutureTask.java:262)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
	at java.lang.Thread.run(Thread.java:744)