title: Ant not running under new Jenkins config
body: <p>I am re-setting up Jenkins 1.5888 on our Mac OS X box. I have googled much about this problem and have come up with the following steps.</p>
  
  <p>I upgraded all plugins as requested.</p>
  
  <p>From Configure System, I set up the Ant plugin to automatically download from the Apache site. I have called this installation Default.</p>
  
  <p>I added and invoke ant step to my build. I selected Default a my ant installation</p>
  
  <p>I ran the build. Here is the part of the output that is causing my frustration:</p>
  
  <p>[participant-test] $ ant -file build.xml clean emma debug install test
  FATAL: command execution failed.Maybe you need to configure the job to choose one of your Ant installations?
  java.io.IOException: Cannot run program "ant" (in directory "/Users/bob/.jenkins/jobs/participant/workspace/participant-test"): error=2, No such file or directory
      at java.lang.ProcessBuilder.start(ProcessBuilder.java:1047)
      at hudson.Proc$LocalProc.(Proc.java:244)
      at hudson.Proc$LocalProc.(Proc.java:216)
      at hudson.Launcher$LocalLauncher.launch(Launcher.java:803)
      at hudson.Launcher$ProcStarter.start(Launcher.java:381)
      at hudson.Launcher$ProcStarter.join(Launcher.java:388)
      at hudson.tasks.Ant.perform(Ant.java:217)
      at hudson.tasks.BuildStepMonitor$1.perform(BuildStepMonitor.java:20)
      at hudson.model.AbstractBuild$AbstractBuildExecution.perform(AbstractBuild.java:770)
      at hudson.model.Build$BuildExecution.build(Build.java:199)
      at hudson.model.Build$BuildExecution.doRun(Build.java:160)
      at hudson.model.AbstractBuild$AbstractBuildExecution.run(AbstractBuild.java:533)
      at hudson.model.Run.execute(Run.java:1759)
      at hudson.model.FreeStyleBuild.run(FreeStyleBuild.java:43)
      at hudson.model.ResourceController.execute(ResourceController.java:89)
      at hudson.model.Executor.run(Executor.java:240)
  Caused by: java.io.IOException: error=2, No such file or directory
      at java.lang.UNIXProcess.forkAndExec(Native Method)
      at java.lang.UNIXProcess.(UNIXProcess.java:184)
      at java.lang.ProcessImpl.start(ProcessImpl.java:130)
      at java.lang.ProcessBuilder.start(ProcessBuilder.java:1028)
      ... 15 more
  Build step 'Invoke Ant' marked build as failure</p>
  
  <p>I can run ant from the command line just fine for the same exact build. I've been at this for a day. I've found some similar issues that appear to be for older versions of Jenkins and don't seem to apply.</p>