in PMD.php, copying the Linux line and changing the index to Darwin seems work on Mac OS X v 10.5.6:
Darwin' => 'java -cp "resources/utility/pmd/Yasca-PMD.jar:resources/utility/pmd/pmd14-4.2.5.jar:resources/utility/pmd/asm-3.1.jar:resources/utility/pmd/jaxen-1.1.1.jar:resources/utility/pmd/retroweaver-rt-2.0.5.jar:resources/utility/pmd/backport-util-concurrent.jar" net.sourceforge.pmd.PMD $DIR net.sourceforge.pmd.renderers.YascaRenderer',
Added for v2.1. Thank you!
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