Ant build won't run in Eclipse

Question

I have an Ant build.xml which no longer runs when launched in Eclipse.
I click on the External Tools Configuration, select the Ant Build I've been running, and click Run.
Nothing happens -- no console window and the build doesn't appear to launch (the classes are not compile nor is the WAR file created).

I recently added a plugin (Spring IDE), this is the only thing I can think of that has changed recently as far as my Eclipse configuration.
I can run the Ant build fine from the command line.

Can anyone suggest where I might look to track down my error?

I'm using the Eclipse Helios release, Build id: 20100617-1415 on Windows XP.

Answer 1

As per pstanton's comment this symptom will occur if your ANT_HOME folder is not correctly defined in Eclipse. Eclipse seems to ignore the ANT_HOME system property.

window->preferences->ant->runtime->Classpath Tab

Answer 2

I faced same problem today , reason behind this was ANT_HOME path variable explained in other answers also.

Initially I added ANT_HOME at 2 places given below and it was not working.

window->preferences->ant->runtime->properties Tab

window->preferences->ant->runtime->Classpath Tab

But when I remove Classpath tab ant home entry ( by setting it to default using Restore default option on right bottom of preferences window ) it worked :). So far it is just a surprise for me because I added same ant home path at both the places.