NetBeans 6.7RC1 Crashes on Mac OS X 10.5.7
After an hour of searching, I found that the problem for me was that java 1.5 on mac was forcing netbeans to run in 64bit mode which was causing it to crash before it even opened.
By following the instructions (reposted with more info) at http://blogs.sun.com/yakshaving/entry/netbeans_will_not_start_on) I was able to get things resolved. As far as I can tell, I have not affected anything else I have.