simpleApp fails building the second time

[Avi Schwartz <enhydra@xxxxxxxxxxxxxxxxxxx>]

Hi,

I am running enhydra enterprise 6.0.1 on a Linux box and trying to go 
through the tutorial.  I used the appwizard to generate the code for 
simpleApp but I have a strange problem.  I can built the application 
only once.  The first time I build it using enhydra-ant it builds and 
runs fine.  However if I try to build it a second time (and it does not 
matter whether I did or didn't make any changes to the code), the build 
fails in presentation/build/build-deploy.xml in the "Build the jar file" 
section.  The error I am getting is:

deploy_presentation:
    [copy] Copying 2 files to 
/home/avi/myProjects/simpleApp/application/bin/webapps/autoload/simpleApp_pres
    [copy] Copying 1 file to 
/home/avi/myProjects/simpleApp/application/bin/webapps/autoload/simpleApp_pres
    [copy] Copying 20 files to 
/home/avi/myProjects/simpleApp/application/bin/webapps/autoload/simpleApp_pres/doc/specification
    [copy] Copying 27 files to 
/home/avi/myProjects/simpleApp/application/bin/webapps/autoload/simpleApp_pres/doc/presentation

BUILD FAILED
file:/home/avi/myProjects/simpleApp/presentation/build/build-deploy.xml:209: 
problem reading 
/home/avi/myProjects/simpleApp/application/bin/webapps/autoload/simpleApp_pres/WEB-INF/lib/simpleApp.jar

This is the ant code that fails:

  <!-- Build the jar file -->
  <jar jarfile="${presentation.dir}/WEB-INF/lib/${project.name}.jar">
   <fileset dir="../../specification/classes"/>
   <fileset dir="../../presentation/classes"/>
  </jar>


At some point I deleted the simpleApp.jar file to see if it has some 
problems with permissions but it did not help.  Deleting the whole 
application and starting over works, but obviously this is not a good 
solution :-)

Any ideas what may the problem be?

Thanks,
Avi