Oracle.jdbc.driver.LogicalConnection erro

Pessoal,
tenho uma aplicação feita em ADF e que roda no OAS. Ela começa funcionando blz, até que de repente a aplicação p/ usuário trava, e no log, aparece o erro:

 [code]java.sql.SQLException: Tentativa de usar um handle inv?lido : 'oracle_jdbc_driver_LogicalConnection_Proxy@222596c1'.
    at oracle.oc4j.sql.spi.ConnectionHandle.oc4j_intercept(ConnectionHandle.java:286)
    at oracle_jdbc_driver_LogicalConnection_Proxy.prepareStatement()
    at oracle.jbo.server.DBTransactionImpl.createPreparedStatement(DBTransactionImpl.java:3399)
    at oracle.jbo.server.DBTransactionImpl2.createPreparedStatement(DBTransactionImpl2.java:428)
    at oracle.jbo.server.DBTransactionImpl.createReUsePreparedStatement(DBTransactionImpl.java:4239)
    at oracle.jbo.server.ViewObjectImpl.getPreparedStatement(ViewObjectImpl.java:8202)
    at oracle.jbo.server.QueryCollection.buildResultSet(QueryCollection.java:746)
    at oracle.jbo.server.QueryCollection.executeQuery(QueryCollection.java:666)
    at oracle.jbo.server.ViewObjectImpl.executeQueryForCollection(ViewObjectImpl.java:3655)
    at oracle.jbo.server.ViewRowSetImpl.execute(ViewRowSetImpl.java:742)
    at oracle.jbo.server.ViewRowSetImpl.executeQueryForMasters(ViewRowSetImpl.java:891)
    at oracle.jbo.server.ViewRowSetImpl.executeQueryForMode(ViewRowSetImpl.java:805)
    at oracle.jbo.server.ViewRowSetImpl.executeQuery(ViewRowSetImpl.java:799)
    at oracle.jbo.server.ViewObjectImpl.executeQuery(ViewObjectImpl.java:3575)
    at com.evermind.server.http.ServletRequestDispatcher.invoke(ServletRequestDispatcher.java:621)
    at com.evermind.server.http.ServletRequestDispatcher.forwardInternal(ServletRequestDispatcher.java:370)
    at com.evermind.server.http.HttpRequestHandler.doProcessRequest(HttpRequestHandler.java:871)
    at com.evermind.server.http.HttpRequestHandler.processRequest(HttpRequestHandler.java:453)
    at com.evermind.server.http.AJPRequestHandler.run(AJPRequestHandler.java:302)
    at com.evermind.server.http.AJPRequestHandler.run(AJPRequestHandler.java:190)
    at oracle.oc4j.network.ServerSocketReadHandler$SafeRunnable.run(ServerSocketReadHandler.java:260)
    at com.evermind.util.ReleasableResourcePooledExecutor$MyWorker.run(ReleasableResourcePooledExecutor.java:303)
    at java.lang.Thread.run(Thread.java:595)

[/code]

   Alguém tem alguma idéia do q possa ser e de como resolver?