WM reported that he'd made some changes in the source tree of eXist 1.4 to enable us to build Cocoon with it, and sent some instructions, which I tried to follow. It looks promising, but it's not quite working yet. Here are the steps I followed using Cocoon 2.1.11 and eXist 1.4rc:

1. Replaced the build.xml, exist-gump.xsl and exist-jars.xsl with the ones from here:
   
   http://exist.svn.sourceforge.net/viewvc/exist?view=rev&revision=10205
2. Downloaded a fresh Cocoon 2.1.11.
3. Patched the Cocoon blocks.properties with a local.blocks.properties which disables Lucene and querybean, per WM's instructions.
4. Tried to run the eXist build.sh:

       ./build.sh -f build/scripts/cocoon/build.xml

   I got several errors caused by 503s from the W3C server, which doesn't really want to deliver the XHTML 1.0 Transitional DTD which is referenced by the exist-jars.xsl file. This appears to be a standard response from the W3C servers, to avoid excessive traffic on those files.
5. Edited that file to point to a local copy of the DTD, and downloaded the DTD and .ent files into the same folder as the XSL file.
6. Tried to run a build again; this time it failed on a missing jars.xml file in the Cocoon tree, which I realized had been deleted by the previous attempt to build. I think it's initially read and removed, then replaced at the end of the process, but if the build dies in the middle you have to replace it.
7. Restored the Cocoon tree to its original state (leaving the local.blocks.properties in place).
8. Successfully built eXist.
9. Tried to build Cocoon, but it failed with this error:

    Warning!
     [ERROR] File core/avalon-framework-api-4.3.jar appears in the lib/ directory,
     but is not declared in lib/jars.xml.
   
     Please update the lib/jars.xml file to include the core/avalon-framework-api-4.3.jar
     file together with a description.
   
   : Fatal Error! Stylesheet directed termination
   home/mholmes/cocoon_with_exist/cocoon-2.1.11/tools/src/check-jars.xsl:161:40: Fatal Error! Fatal error during transformation Cause: Fatal error during transformation
   Failed to process /home/mholmes/cocoon_with_exist/cocoon-2.1.11/lib/jars.xml
   
   BUILD FAILED
   /home/mholmes/cocoon_with_exist/cocoon-2.1.11/tools/targets/validate-build.xml:72: Fatal error during transformation
   

Reported back to WM. I think we'll get there eventually, and I think this work is actually necessary in order to give us a Cocoon/eXist block with 1.4 (one of the standard distro formats).

This is similar to the errors I was getting previously. The file seems to be a standard part of Cocoon 2.1.11.