io.keikai.importer.ImportException: Fail to import stylesheet from book repro.xlsx
	at io.keikai.importer.XlsxImporter.imports(XlsxImporter.java:273)
	at io.keikai.range.impl.imexp.ExcelImportAdapter.imports(ExcelImportAdapter.java:48)
	at io.keikai.api.impl.ImporterImpl.imports(ImporterImpl.java:58)
	at io.keikai.api.impl.ImporterImpl.imports(ImporterImpl.java:90)
	at io.keikai.api.impl.ImporterImpl.imports(ImporterImpl.java:77)
	at io.keikai.app.repository.impl.SimpleRepository.load(SimpleRepository.java:62)
	at io.keikaiex.app.impl.BookManagerEx.readBook(BookManagerEx.java:62)
	at io.keikai.app.ui.dlg.OpenManageBookCtrl.loadBook(OpenManageBookCtrl.java:202)
	at io.keikai.app.ui.dlg.OpenManageBookCtrl.onOpen(OpenManageBookCtrl.java:100)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.zkoss.zk.ui.select.Selectors$ComposerEventListener.onEvent(Selectors.java:687)
	at org.zkoss.zk.ui.AbstractComponent.onEvent(AbstractComponent.java:3184)
	at org.zkoss.zk.ui.AbstractComponent.service(AbstractComponent.java:3154)
	at org.zkoss.zk.ui.AbstractComponent.service(AbstractComponent.java:3096)
	at org.zkoss.zk.ui.impl.EventProcessor.process(EventProcessor.java:138)
	at org.zkoss.zk.ui.event.Events.sendEvent(Events.java:353)
	at org.zkoss.zk.ui.event.Events.sendEvent(Events.java:377)
	at org.zkoss.zk.ui.AbstractComponent$ForwardListener.onEvent(AbstractComponent.java:3629)
	at org.zkoss.zk.ui.AbstractComponent.onEvent(AbstractComponent.java:3184)
	at org.zkoss.zk.ui.AbstractComponent.service(AbstractComponent.java:3154)
	at org.zkoss.zk.ui.AbstractComponent.service(AbstractComponent.java:3096)
	at org.zkoss.zk.ui.impl.EventProcessor.process(EventProcessor.java:138)
	at org.zkoss.zk.ui.impl.UiEngineImpl.processEvent(UiEngineImpl.java:1890)
	at org.zkoss.zk.ui.impl.UiEngineImpl.process(UiEngineImpl.java:1662)
	at org.zkoss.zk.ui.impl.UiEngineImpl.execUpdate(UiEngineImpl.java:1329)
	at org.zkoss.zk.au.http.DHtmlUpdateServlet.process(DHtmlUpdateServlet.java:611)
	at org.zkoss.zk.au.http.DHtmlUpdateServlet.doGet(DHtmlUpdateServlet.java:487)
	at org.zkoss.zk.au.http.DHtmlUpdateServlet.doPost(DHtmlUpdateServlet.java:495)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
	at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511)
	at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:401)
	at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
	at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
	at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:766)
	at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:450)
	at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
	at org.mortbay.jetty.Server.handle(Server.java:326)
	at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
	at org.mortbay.jetty.HttpConnection$RequestHandler.content(HttpConnection.java:945)
	at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:756)
	at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:218)
	at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
	at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:410)
	at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:582)
Caused by: java.lang.NullPointerException
	at io.keikai.importer.XlsxExtractor$XlsxPatternExtractor.getFgColor(XlsxExtractor.java:770)
	at io.keikai.importer.XlsxImporter.importFills(XlsxImporter.java:603)
	at io.keikai.importer.XlsxImporter.importStyleSheet(XlsxImporter.java:533)
	at io.keikai.importer.XlsxImporter.imports(XlsxImporter.java:194)
	... 47 more