Netbeans debugger won't recognize Glassfish server

Here's what I've done so far:

1. Did a fresh build of project (web service project).
2. Redeployed project war file to Glassfish server.
3. Restarted server with --debug=true.
4. Attached debugger from Netbeans.

Debugger attaches to the server without an error (responds "User Program Running"), however the Debug tab (in the Projects/Files/Services window) with all the different services that are supposed to get attached fails to show up as it did when everything was working.

When I try to start debugging the project, the server dropdown doesn't have any servers in it, and it won't let me start debugging without selecting a server.

Glassfish version is 2.1.1. Netbeans version is 7.4 Patch 3. JRE version is 1.7.0_79-b15.

I'm a bit of a Netbeans newbie, so I apologize if I've left out any information that's important. Can someone see what I'm doing wrong?