Thanks Justin.
That would have made things easy, however, there was no xml file in the '_promaps_cache' directory. The required xml file is not being created.
I created a blank xml file called '_promaps_geocache.xml' and uploaded it to the directory. However it does not get updated when viewing the map (tried many times). The '_promaps_cache' directory and the '_promaps_geocache.xml' have 755 permissions.
How do I troubleshoot this?