I realize that this is a old thread but I also had a difficult time finding out how to debug php with Aptana Studio and FireFox so here is a quick how-to to get it working...
The easiest way I found is to install wamp server V2.2, this is a very useful program as it installs Apache Server, PHP and MySQL and other tools, everything can be easily configured via the taskbar.
1.) Install Aptana Studio V3.3.X or higher Download here
2.) Install WampServer V2.2 or higher Download here (XAMMP users read bottom).
WampServer:
1.) Make sure XDebug is accepting remote debug, click on the WampServer icon in the taskbar and go to PHP->PHP Setting and make sure that "(XDebug): Remote debug" is checked if not select it click on the WampServer icon and "Restart all services".
2.) Verify that XDebug is running:
a.) If you had WampServer insert index.php enter "localhost" in the URL and under "Tools" click "phpinfo()" and check to make sure XDebug is running, you should see the following in FireFox:
b.) If you didn't overwrite the index.php create a file (/www_dir/phpinfo.php) with the following:
<?php
phpinfo();
?>
b.1) In FireFox enter "localhost/phpinfo.php" and look for XDebug as shown in the previous image.
Aptana Studio:
1.) Click Window->Preferences
2.) In the Preferences dialog go to Aptana Studio->Editors->PHP->PHP Interpreters
3.) Click "Add..."
4.) Enter the information like
5.) Click "OK"
6.) Click on the debug icon and select "Debug Configurations"
7.) Double click on "PHP Web Page"
8.) Click the plus next to "PHP Server"
a.) Enter a name
b.) Base URL will be "localhost"
c.) Document Root will be the path to your index.php
Finally in Aptana Studio click the Debug Icon Arrow and select the configuration you named above. If Firefox prompts you install the Aptana Studio plugin...
Hope this helps out...
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XAMPP USERS
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Follow the steps provided but your directory link in the
In the Preferences dialog go to Aptana Studio->Editors->PHP->PHP Interpreters
should link to C:\xampp\php\php.exe and C:\xampp\php\php.ini respectively
***** UPDATE *****
If you are using Firefox V20+ there are some compatibility problems with Firebug V1.8+ that basicly breaks Firefox's context menus, I could not find a fix for it so I ended up having to go another route and figured I should make a post, Aptana Studio is based on Eclipse so the best way IMHO to get PHP Debugging is to install Eclipse with PDT and remove Aptana Studio... The above instructions will work to get everything working with XDebug
Here is a nice link on how to get everything up and running eclipse-pdt