Adding a pptx into Confluence fails with "There was a problem converting this attachment"

 -- referer: http://confluence:8090/display/TEST/Test+pttx | url: /plugins/servlet/pptslide | userName: admin
2014-09-25 11:15:22,901 WARN [http-bio-8090-exec-3] [com.benryan.conversion.PPTSlideServlet] doGet Conversion task timed out for attachment : junk.pptx with page number 0, waited : 300, now executing in background.
 -- referer: http://confluence:8090/display/TEST/Test+pttx | url: /plugins/servlet/pptslide | userName: admin
2014-09-25 11:15:23,216 ERROR [DefaultSlideCacheManager:thread-1] [com.benryan.conversion.AbstractSlideConversionTask] call problem while converting junk.pptx
 -- referer: http://confluence:8090/display/TEST/Test+pttx | url: /plugins/servlet/pptslide | userName: admin
java.lang.NumberFormatException: For input string: "f0"
	at sun.misc.FloatingDecimal.readJavaFormatString(FloatingDecimal.java:1241)
	at java.lang.Double.parseDouble(Double.java:540)
	at com.benryan.escher.XmlCustomShapeRenderer.getDouble(XmlCustomShapeRenderer.java:170)
	at com.benryan.escher.XmlCustomShapeRenderer.convertPoint(XmlCustomShapeRenderer.java:165)
	at com.benryan.escher.XmlCustomShapeRenderer.renderCustomShape(XmlCustomShapeRenderer.java:83)
	at com.benryan.escher.EscherRenderer.renderAutoshape(EscherRenderer.java:551)
	at com.benryan.escher.EscherRenderer.walkShapes(EscherRenderer.java:233)
	at com.benryan.ppt.PptRenderer.render(PptRenderer.java:125)
	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:745)
2014-09-25 11:15:26,274 WARN [http-bio-8090-exec-3] [jersey.spi.inject.Errors] processErrorMessages The following warnings have been detected with resource and/or provider classes:
  WARNING: A HTTP GET method, public javax.ws.rs.core.Response com.atlassian.confluence.tinymceplugin.rest.DraftsResource.getDrafts(int,int), should not consume any entity.
 -- referer: http://confluence:8090/display/TEST/Test+pttx | url: /rest/tinymce/1/content/2228226.json | userName: admin