1) Ant 1.9.1 or older is used.
2) A build file imports Clover's tasks from the clover.jar, e.g.:
<taskdef resource="cloverlib.xml" classpath="clover-4.0.2.jar"/> <clover-env/>
3) An attempt to run a build fails with an error like:
BUILD FAILED Error reading project file jar:file:/path/to/clover-4.0.2.jar!/cloverlib.xml: central directory zip64 extended information extra field's length doesn't match central directory data. Expected length 0 but is 16
This is caused by a bug in zip64 implementation and has been fixed in Ant 1.9.2 (release notes).
Upgrade to Ant 1.9.2 or newer.