These instructions are pretty out of date, and a ton of work has gone into packaging OpenNMS for most major distributions.

 Please do yourself a favor and check out the OpenNMS web site at http://www.opennms.org/ and see if the download instructions are appropriate for your distribution before attempting to build from source.

 Also keep in mind that while 1.5.9x is still technically unstable, it is at least as stable as the 1.2.x series, and is recommended for new installs.