java.lang.ClassNotFoundException——在什么地方能看到出错的是哪张报表吗？

java.lang.ClassNotFoundException——50个豆求问大家！在什么地方能看到出错的是哪张报表呢？
tomcat警告如下:
java.lang.ClassNotFoundException:
      at java.lang.Class.forName0(Native Method)
      at java.lang.Class.forName(Class.java:264)
      at com.fr.data.pool.MemoryConnection.getDefaultValidationQuery(Unknown Source)
      at com.fr.data.pool.MemoryConnection.getDataSource(Unknown Source)
      at com.fr.data.pool.MemoryConnection.create(Unknown Source)
      at com.fr.data.impl.JDBCDatabaseConnection.createConnection(Unknown Source)
      at com.fr.data.impl.DatabaseDictionary.asTableData(Unknown Source)
      at com.fr.data.impl.FormulaDisplayDictionary.createKVS(Unknown Source)
      at com.fr.data.impl.FormulaDisplayDictionary.entrys(Unknown Source)
      at com.fr.form.ui.ComboBoxDataFilter.filterAndPutData(Unknown Source)
      at com.fr.form.ui.ComboBox.filterAndPutData(Unknown Source)
      at com.fr.form.ui.ComboBox.createJSONData(Unknown Source)
      at com.fr.web.core.A.eA.A(Unknown Source)
      at com.fr.web.core.A.RA.actionCMD(Unknown Source)
      at com.fr.web.core.WebActionsDispatcher.dealForActionCMD(Unknown Source)