Also look for a configuration setting that references your IP instead of your domain name.
I don't believe that your issue is with the way XAMPP is configured by default because Apache is listening on port 80 for any connection be it IP or domain name.
In the web root folder you have a .htaccess file which should have the RewriteBase /bam
uncommented as per these instructions:http://docs.elgg.org/wiki/Installation
Here is something you could try and that is to put your web site directly in the htdocs folder (DocumentRoot/web root folder) ie not in a folder of it's own and delete the 2 index file that belong to XAMPP.
See these troubleshooting tips:http://docs.elgg.org/wiki/Install_Troubleshooting
Did you follow these XAMPP specific instructions - but my method of directly adding your web site to the htdocs folder is still worth considering:http://docs.elgg.org/wiki/Install_XAMPP
Finally and very important, XAMPP is not meant for use in a production environment open to the public because of security concerns, but rather it is designed for development use at localhost level only.
So I can't recommend XAMPP for your intended purpose - see Zend Server (CE)
for a free production environment server ( thank Altrea