Custom drupal 7 batch xml sitemap module

I have a listing website on drupal 7 at [login to view URL], I am currently using xml sitemap ([login to view URL]) I tried using updated versions and dev version of the module but it takes way too long and fails most of the time. I need to generate xml sitemap with 50k listing on each page. I need this done now. Currently whenever I try to rebuild the sitemap I get error "An AJAX HTTP request terminated abnormally. Debugging information follows. Path: /batch?id=5907&op=do StatusText: error ResponseText: ReadyState: 0". So at this point I want different custom solution.