Jasperreports-help

olá pessoal , estou corrigindo uma aplicação com alguns relatorios em jasper reports ( nunca nem mechi com isso), porem algumas vezes qunado chamo esses relatorios eles carregam e outras apresenta o seguinte erro:

java.io.FileNotFoundException: o:\oracle\isuites\apache\apache\ProdAcumTipo.java (The requested operation cannot be performed on a file with a user-mapped section open) at java.io.FileOutputStream.open(Native Method) at java.io.FileOutputStream.(FileOutputStream.java, Compiled Code) at java.io.FileOutputStream.(FileOutputStream.java, Compiled Code) at java.io.FileOutputStream.(FileOutputStream.java, Compiled Code) at java.io.FileWriter.(FileWriter.java:43) at net.sf.jasperreports.engine.util.JRSaver.saveClassSource(JRSaver.java, Compiled Code) at net.sf.jasperreports.engine.design.JRAbstractClassCompiler.compileReport(JRAbstractClassCompiler.java, Compiled Code) at net.sf.jasperreports.engine.design.JRDefaultCompiler.compileReport(JRDefaultCompiler.java, Compiled Code) at net.sf.jasperreports.engine.JasperCompileManager.compileReport(JasperCompileManager.java, Compiled Code) at _rpr._RelatProdAcum03._jspService(_RelatProdAcum03.java, Compiled Code) at oracle.jsp.runtime.HttpJsp.service(HttpJsp.java, Compiled Code) at oracle.jsp.app.JspApplication.dispatchRequest(JspApplication.java, Compiled Code) at oracle.jsp.JspServlet.doDispatch(JspServlet.java, Compiled Code) at oracle.jsp.JspServlet.internalService(JspServlet.java, Compiled Code) at oracle.jsp.JspServlet.service(JspServlet.java, Compiled Code) at javax.servlet.http.HttpServlet.service(HttpServlet.java, Compiled Code) at org.apache.jserv.JServConnection.processRequest(JServConnection.java, Compiled Code) at org.apache.jserv.JServConnection.run(JServConnection.java, Compiled Code) at java.lang.Thread.run(Thread.java, Compiled Code) NESTED BY : net.sf.jasperreports.engine.JRException: Error saving expressions class file : o:\oracle\isuites\apache\apache\ProdAcumTipo.java at net.sf.jasperreports.engine.util.JRSaver.saveClassSource(JRSaver.java, Compiled Code) at net.sf.jasperreports.engine.design.JRAbstractClassCompiler.compileReport(JRAbstractClassCompiler.java, Compiled Code) at net.sf.jasperreports.engine.design.JRDefaultCompiler.compileReport(JRDefaultCompiler.java, Compiled Code) at net.sf.jasperreports.engine.JasperCompileManager.compileReport(JasperCompileManager.java, Compiled Code) at _rpr._RelatProdAcum03._jspService(_RelatProdAcum03.java, Compiled Code) at oracle.jsp.runtime.HttpJsp.service(HttpJsp.java, Compiled Code) at oracle.jsp.app.JspApplication.dispatchRequest(JspApplication.java, Compiled Code) at oracle.jsp.JspServlet.doDispatch(JspServlet.java, Compiled Code) at oracle.jsp.JspServlet.internalService(JspServlet.java, Compiled Code) at oracle.jsp.JspServlet.service(JspServlet.java, Compiled Code) at javax.servlet.http.HttpServlet.service(HttpServlet.java, Compiled Code) at org.apache.jserv.JServConnection.processRequest(JServConnection.java, Compiled Code) at org.apache.jserv.JServConnection.run(JServConnection.java, Compiled Code) at java.lang.Thread.run(Thread.java, Compiled Code) net.sf.jasperreports.engine.JRException: Error saving expressions class file : o:\oracle\isuites\apache\apache\ProdAcumTipo.java

gostaria de ajuda para entender o que esse erro que dizer o que esta acontecendo? é um problema na copilação? o q pode estar gerando esse problema?