Eclipse 3.7 now includes a newer version of Ant, so we need to fix the classpath used in the Eclipse external build launcher.
I've got a fix and will submit soon, after testing.
Submitted fix as pull request https://github.com/sgothel/jogl/pull/42. The commit is at https://github.com/WadeWalker/jogl/commit/701ee2108fe84422d4ec9ae3b22cfb7bc6f30c59.
I tested building gluegen and jogl with Java 1.7.0_02 and Eclipse Indigo SR1 on Win 7, CentOS, and OS X, and it works (with this fix) on all three.