Problems debugging with Komodo IDE

I've been trying to debug a problem with my .install file for a module I wrote using Komodo 4.1 and xdebug (with the Xdebug Helper Firefox add-on), and I'm having a problem. I turn on the debugger and click on Submit on the Modules admin page. The debugging starts at line 12 in index.php, I have a breakpoint in my install file, but for some reason it never gets there. Instead, the Debugging Options dialog box comes up instead, and debugging stops. I've read everything I can find on debugging in Komodo , but I can't figure out why the Debugging Options dialog box keeps coming up. Can anyone explain why this happens and how I can get around it so I can get on with my debugging?

Thanks.