Viewfile is unable to display PDF file

2010-09-21 12:05:25,866 ERROR [DefaultSlideCacheManager:thread-1] [com.benryan.conversion.SlideConversionThread] run problem while converting mypdftest.pdf
 -- url: /confluence/plugins/servlet/pptslide | userName: admin
java.lang.NullPointerException
	at com.sun.pdfview.PDFFile.readTrailer15(PDFFile.java:1289)
	at com.sun.pdfview.PDFFile.readTrailer(PDFFile.java:1104)
	at com.sun.pdfview.PDFFile.parseFile(PDFFile.java:1377)
	at com.sun.pdfview.PDFFile.<init>(PDFFile.java:125)
	at com.sun.pdfview.PDFFile.<init>(PDFFile.java:101)
	at com.benryan.conversion.SlideConversionThread.convertFile(SlideConversionThread.java:75)
	at com.benryan.conversion.SlideConversionThread.run(SlideConversionThread.java:123)
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:441)
	at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
	at java.util.concurrent.FutureTask.run(FutureTask.java:138)
	at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)