Same setup with mine, except I don't use XAMPP and went straight for the mysql/apache/php installs. I haven't used DW in over a year, but personally (I'm a mainly backend person, so keep that in mind) I prefer the eclipse over it - free is a bonus
Is the error you're receiving as a console result, or is it a popup? The only problems I've had in the past is with the popups, and I also found that the run (not the debug) has issues with using intercepting filters (a pattern I built, it doesn't like to run through it so I have to debug or do it though cli / browser). As for the popup dialog it gives, I've received this when I didn't properly configure the plugin for eclipse.
The best suggestion I can make for trying right now would be to upgrade the zend plugin. Help > Software Updates > Manage Configuration > In the tree select the Zend debugger > Scan for updates. I believe the newest is 5.2.15, though I'm using the 5.2.12 - I had configuration issues with 5.2.15, so I'm waiting for a PHP5.3 compatible plugin (so I can run namespaces without the editor complaining).
Also note that if you need to make use of external resources (such as mysql/mysqli or other database extensions), you'll need to alter the ini file in the plugin folder or change the path for the ini to a current one using Window > Preferences > PHP > PHP Executables, or by reconfiguring the cli with the necessary extension loading. The default one is bold, but I've found that it won't let me edit the default ones, but you can create you're own. I have mine setup with the executable path to the plugin's php-cgi.exe, and the ini set to my server's php.ini fle.
I believe that this environment is actually independent of you're apache environment. I have run through the eclipse with apache off, and it seemed to work just fine.
Hope that helps!