I am getting a lot of these errors while trying to build gwtp+mgwt app using ant-
Preparing method tabBarMoreImage
[java] [ERROR] An error occurred while trying to write the image bundle.
[java] javax.imageio.IIOException: Can't create output stream!
[java] at javax.imageio.ImageIO.write(ImageIO.java:1560)
...
Preparing method tabBarMostRecentImage
[java] [ERROR] An error occurred while trying to write the image bundle.
[java] javax.imageio.IIOException: Can't create output stream!
...
[java] Caused by: javax.imageio.IIOException: Can't create cache file!
[java] at javax.imageio.ImageIO.createImageOutputStream(ImageIO.java:397)
[java] at javax.imageio.ImageIO.write(ImageIO.java:1558)
[java] ... 33 more
[java] Caused by: java.io.IOException: Too many open files
[java] at java.io.UnixFileSystem.createFileExclusively(Native Method)
[java] at java.io.File.checkAndCreate(File.java:1704)
[java] at java.io.File.createTempFile(File.java:1792)
[java] at javax.imageio.stream.FileCacheImageOutputStream.(FileCacheImageOutputStream.java:71)
[java] at com.sun.imageio.spi.OutputStreamImageOutputStreamSpi.createOutputStreamInstance(OutputStreamImageOutputStreamSpi.java:50)
[java] at javax.imageio.ImageIO.createImageOutputStream(ImageIO.java:393)
[java] ... 34 more
[java] Preparing method getButtonBarArrowDownImage
[java] [ERROR] An error occurred while trying to write the image bundle.
[java] javax.imageio.IIOException: Can't create output stream!
[java] at javax.imageio.ImageIO.write(ImageIO.java:1560)
[java] at com.google.gwt.resources.rg.ImageBundleBuilder.createImageBytes(ImageBundleBuilder.java:558)
[java] at com.google.gwt.resources.rg.ImageBundleBuilder.toPng(ImageBundleBuilder.java:544)
...
The application runs fine in dev mode. Any ideas?