"Content is not allowed in prolog" error importing QTI zip file

Steps
create a new test
export it
in another site, import the export zip file
the test will not be imported.
checking the tomcat logs there's an error
15-Jun-2018 10:27:36.900 DEBUG [http-nio-8980-exec-4] org.etudes.mneme.impl.PoolServiceImpl.allowManagePools allowManagePools: 546076f7-7b0d-4484-8e43-fa3d25f0cb81
[Fatal Error] catalog.xml:1:1: Content is not allowed in prolog.
org.xml.sax.SAXParseException; systemId: file:/usr/local/apache-tomcat-8.5.31-for-sakai-12.1-dev-uh/webapps/etudes-mneme-tool/WEB-INF/classes/catalog.xml; lineNumber: 1; columnNumber: 1; Content is not allowed in prolog.
    at com.sun.org.apache.xerces.internal.parsers.DOMParser.parse(DOMParser.java:257)
    at com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderImpl.parse(DocumentBuilderImpl.java:339)
    at javax.xml.parsers.DocumentBuilder.parse(DocumentBuilder.java:150)
    at org.etudes.mneme.tool.UploadXml.setUpload(UploadXml.java:83)
    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.etudes.ambrosia.impl.UiPropertyReference.setFileValue(UiPropertyReference.java:802)
    at org.etudes.ambrosia.impl.UiPropertyReference.write(UiPropertyReference.java:438)
    at org.etudes.ambrosia.impl.UiDecoder.decode(UiDecoder.java:149)
    at org.etudes.ambrosia.impl.UiServiceImpl.decode(UiServiceImpl.java:202)
    at org.etudes.mneme.tool.ImportQtiView.post(ImportQtiView.java:124)
    at org.etudes.ambrosia.util.AmbrosiaServlet.doPost(AmbrosiaServlet.java:236)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:661)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:742)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.sakaiproject.util.RequestFilter.doFilter(RequestFilter.java:418)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:728)
    at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:470)
    at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:356)
    at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:316)
    at org.sakaiproject.tool.impl.ActiveToolComponent$MyActiveTool.forward(ActiveToolComponent.java:513)
    at org.sakaiproject.portal.charon.SkinnableCharonPortal.forwardTool(SkinnableCharonPortal.java:1488)
    at org.sakaiproject.portal.charon.handlers.SiteHandler.doToolBuffer(SiteHandler.java:1227)
    at org.sakaiproject.portal.charon.handlers.SiteHandler.bufferContent(SiteHandler.java:1061)
    at org.sakaiproject.portal.charon.handlers.SiteHandler.doSite(SiteHandler.java:490)
    at org.sakaiproject.portal.charon.handlers.SiteHandler.doGet(SiteHandler.java:266)
    at org.sakaiproject.portal.charon.handlers.SiteHandler.doGet(SiteHandler.java:154)
    at org.sakaiproject.portal.charon.handlers.WorksiteHandler.doPost(WorksiteHandler.java:69)
    at org.sakaiproject.portal.charon.SkinnableCharonPortal.doPost(SkinnableCharonPortal.java:1172)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:661)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:742)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.sakaiproject.util.RequestFilter.doFilter(RequestFilter.java:467)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:496)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81)
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:650)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342)
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:803)
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:790)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1468)
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:748)
sakaicontrib / mneme-project

"Content is not allowed in prolog" error importing QTI zip file #18
