I believe the issue here is when renaming ht.access to .htaccess and using SEF URL’s, you receive an internal server error (somebody correct me if wrong). This is most likely caused by the PHP directives in the ht.access distributed with the product, or it is possible you have not enabled mod_rewrite in your Apache distribution (I believe XAMPP requires editing Apache’s httpd.conf file to activate the mod_rewrite module).
PHP Directives:
php_flag zlib.output_compression On
php_value zlib.output_compression_level 5
should be commented:
#php_flag zlib.output_compression On
#php_value zlib.output_compression_level 5
If mod_rewrite is enabled, and commenting the PHP directives doesn’t work, the only other thing it could be is you have installed in a subdirectory and need to add the absolute path to the web root in the RewriteRule for MODx’s SEF feature.
For instance, if you are in the subdirectory /modx/ within your web server root, change the RewriteRule to this...
RewriteRule ^(.*)$ /modx/index.php?q=$1 [L,QSA]
I hope that helps and someone can help translate if it makes no sense...