There is a directory missing which causes ant to fail.
/home/guenter/workspace/lucene/nutch-0.7.1/build.xml:76: The following error occurred while executing this line:
/home/guenter/workspace/lucene/nutch-0.7.1/src/plugin/build.xml:9: The following error occurred while executing this line:
/home/guenter/workspace/lucene/nutch-0.7.1/src/plugin/build-plugin.xml:85: srcdir "/home/guenter/workspace/lucene/nutch-0.7.1/src/plugin/nutch-extensionpoints/src/java" does not exist!
Compilation worked, when I omitted line 9 in nutch-0.7.1/src/plugin/build.xml:
<!-- <ant dir="nutch-extensionpoints" target="deploy"/> -->
However, I guess that is not what was intended.