Ever since Netbeans 7.2 users have been asking "What happened to the NetBeans plugin needed for older versions of GlassFish"
https://forums.netbeans.org/topic54077.html
http://stackoverflow.com/questions/17313981/unable-to-add-glassfish-v2-1-1-server-to-netbeans-7-3-1-classnotfoundexceptio
The answer was download the file:
org-netbeans-modules-j2ee-sun-appsrv81.nbm
from either of the following locations:
http://dlc.sun.com.edgesuite.net/netbeans/updates/7.1.1/uc/final/certified/modules/extra/org-netbeans-modules-j2ee-sun-appsrv81.nbm
http://dlc.sun.com.edgesuite.net/netbeans/updates/6.9/uc/m1/dev/modules/enterprise/org-netbeans-modules-j2ee-sun-appsrv81.nbm
and install it manually.
This worked fine, but time has moved on and it looks like the server from which the plugin could be downloaded has been retired.
Where can I find this plugin ?