[Building Sakai] Error when using Mneme.

[50600822 at stu.hcmut.edu.vn]

Hi, I got some problem when trying to use Mneme 2.1.2 on Sakai 2.7.1 . when I added this tool to one site and try to add Pool or add Question I got these following error:

org.sakaiproject.portal.api.PortalHandlerException: org.sakaiproject.tool.api.ToolException: Servlet execution threw an exception
    at org.sakaiproject.portal.charon.handlers.ToolHandler.doPost(ToolHandler.java:73)
caused by: org.sakaiproject.tool.api.ToolException: Servlet execution threw an exception
    at org.sakaiproject.portal.charon.SkinnableCharonPortal.forwardTool(SkinnableCharonPortal.java:1221)
caused by: javax.servlet.ServletException: Servlet execution threw an exception
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
caused by: java.lang.Error: java.sql.SQLException: Connection is closed.
    at org.sakaiproject.db.impl.BasicSqlService.transact(BasicSqlService.java:409)
caused by: java.sql.SQLException: Connection is closed.
    at org.apache.commons.dbcp.PoolingDataSource$PoolGuardConnectionWrapper.checkOpen(PoolingDataSource.java:175)
    at org.apache.commons.dbcp.PoolingDataSource$PoolGuardConnectionWrapper.close(PoolingDataSource.java:180)
    at org.sakaiproject.db.impl.BasicSqlService.returnConnection(BasicSqlService.java:276)
    at org.sakaiproject.db.impl.BasicSqlService.transact(BasicSqlService.java:409)
    at org.etudes.mneme.impl.AssessmentStorageSql.insertAssessment(AssessmentStorageSql.java:873)
    at org.etudes.mneme.impl.AssessmentStorageSql.saveAssessment(AssessmentStorageSql.java:461)
    at org.etudes.mneme.impl.AssessmentServiceImpl.save(AssessmentServiceImpl.java:1234)
    at org.etudes.mneme.impl.AssessmentServiceImpl.newAssessment(AssessmentServiceImpl.java:472)
    at org.etudes.mneme.tool.AssessmentsView.post(AssessmentsView.java:280)
    at org.etudes.ambrosia.util.AmbrosiaServlet.doPost(AmbrosiaServlet.java:230)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:647)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:269)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
    at org.sakaiproject.util.RequestFilter.doFilter(RequestFilter.java:585)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:215)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
    at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:659)
    at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:457)
    at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:359)
    at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:311)
    at org.sakaiproject.tool.impl.ActiveToolComponent$MyActiveTool.forward(ActiveToolComponent.java:500)
    at org.sakaiproject.portal.charon.SkinnableCharonPortal.forwardTool(SkinnableCharonPortal.java:1221)
    at org.sakaiproject.portal.charon.handlers.ToolHandler.doTool(ToolHandler.java:204)
    at org.sakaiproject.portal.charon.handlers.ToolHandler.doGet(ToolHandler.java:96)
    at org.sakaiproject.portal.charon.handlers.ToolHandler.doPost(ToolHandler.java:73)
    at org.sakaiproject.portal.charon.SkinnableCharonPortal.doPost(SkinnableCharonPortal.java:1064)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:647)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:269)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
    at org.sakaiproject.util.RequestFilter.doFilter(RequestFilter.java:646)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:215)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:172)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:108)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:174)
    at org.apache.coyote.http11.Http11AprProcessor.process(Http11AprProcessor.java:843)
    at org.apache.coyote.http11.Http11AprProtocol$Http11ConnectionHandler.process(Http11AprProtocol.java:640)
    at org.apache.tomcat.util.net.AprEndpoint$Worker.run(AprEndpoint.java:1293)
    at java.lang.Thread.run(Thread.java:619)

I saw an similiar report here https://jira.sakaiproject.org/browse/KNL-571 . It has even been resolved . But I can't find the kernel-impl/src/main/java/org/sakaiproject/db/impl/BasicSqlService.java in my sakai-src. Can somebody tell me how to fix this.

Thanks in advance.