I installed Apache Tomcat 7.0.28 in my JBuilder6. I use JDK 1.6.0_32 (jre6). I can get http://localhost:8080/ page. However, when I tried to run my JSP file, I encountered following error:

FileUpload.jsp: java.lang.NoClassDefFoundError: org/apache/tools/ant/Task
FileUpload.jsp: Caused by java.lang.NoClassDefFoundError: org.apache.tools.ant.Task
...12 more
Could not find the main class: org.apache.jasper.jspC. Program will exit.

I tried google this error and was not able to find solution.