When running the slave agent as jnlp (launched from website or command line), my java project cannot run. Here is the console output from a failed launch:

--------------
Started by user Jessica Finley
Building remotely on Windows-Java in workspace c:\jenkins-java\workspace\Pixie-Coverage
Cleaning up c:\jenkins-java\workspace\Pixie-Coverage\pixie
Updating http://192.168.0.155/code/trunk/Tech4Learning at revision '2013-08-27T06:16:01.503 -0700'
At revision 21730
no change for http://192.168.0.155/code/trunk/Tech4Learning since the previous build
[pixie] $ cmd.exe /C '"c:\jenkins-java\tools\Ant\Ant_1.8.2\bin\ant.bat -file build.xml -DincludeIntegration=true -Djava.policy.file=c:/jenkins-java/workspace/Pixie-Coverage/pixie/java.policy -Dinstrument.cobertura=true jar.debug && exit %%ERRORLEVEL%%"'
Buildfile: build.xml does not exist!
Build failed
Build step 'Invoke Ant' marked build as failure
Skipping Cobertura coverage report as build was not UNSTABLE or better ...
Recording test results
Sending e-mails to: jeremy@tech4learning.com jfinley@tech4learning.com
Finished: FAILURE
---------------

The build.xml file location is specified in the project configuration. This used to work with an older version of Jenkins (somewhere in 1.4's). We upgraded Jenkins and now it no longer works. If I run the slave agent as a Windows service, the build.xml file can be found (without changing the project configuration). However, this is not a valid work around for our project because our project involves Fest GUI automated testing and we need the slave agent to run in a windowed environment, not headless.