Thank you for being willing to maintain PaperClips. Hopefully the project will receive more love from someone who uses it regularly. :)
Looking at the Hudson builds, the test failures appear to all be IllegalAccessErrors. The test classes are referencing package private methods in the same package. If you run them in Eclipse, they are successful.
My hunch is that Maven is isolating the main and test code into separate classloaders, so the Java runtime sees them as being in separate packages--hence the illegal access.
The simplest solution would probably be to make those methods public, but add a @noreference annotation to the Javadoc stating that the method is for internal use only.
This code has been quite stable for years. Most of the bugs you see in Bugzilla are my wishlist for PaperClips 2. My intention was update the APIs so they would not depend on points so much--however I painted myself into a corner and never finished. This code is still on my personal laptop, and was never checked in anywhere IIRC. Whether you choose to pursue these refactorings further would be up to you.