We need to make sure you are doing everything correctly, so follow the test case below and let us know what happens for you:
1- Go to
https://getfirebug.com/tests/manual/console/joes-original/test.html and open firebug.
2- Switch to the Script panel and enable it, if it isn't already enabled.
3- Select 'test.html' file from the location menu.
4 - Set a breakpoint at line 23.
5- Click the 'log' button on the page.
After the step #5, the breakpoint, you set at the line 23, should get hit. Does this test case work for you? If so, then you could make sure you are not blocked by an issue!
Let's know if you have any problem!
Farshid