Am following the instructions at
www.jboss.org/jbossweb/install/index.html
In particular the relevant paragraph
Downloading JBoss Web
JBoss Web is distributed as a standalone webserver. The distribution can be downloaded directly from the JBossWeb downloads page. JBoss Web is not pure Java. It contains native code, compiled and optimized for each operating operating system. Download the package appropriate for your platform, paying particular attention to whether or not you are running on the 64-bit system.
Uncompress the distribution wherever you would like JBoss Web installed.
Then download the native part from the JBossNative downloads page. And uncompress it in the JBossWeb direction (named like jboss-web-2.1.0.GA/). The files will be installed in the bin subdirectory.