Hi Hughesar
Apologies for the delay.
In version 6.0.28 we now allow the use of internal shortcodes for directing the plugin to the correct directories and URLs for the marker files.
Please go to Maps->Settings (left menu in wp-admin) and have a look at the "MARKER XML DIR" and "MARKER XML URL" fields.
Change them to the following
Marker XML DIR
{uploads_dir}/wp-google-maps/
Marker XML URL
{uploads_url}/wp-google-maps/