we had issues with the map loading on a previous version of store locator so upgraded to the latest version 1.8.10 on Joomla 2.5
with around 90 stores in the admin area nothing is shown up when it loads and no results are shown when you search.
all the settings are the same as before the upgrade which worked great until the api changed on Google
I have sent an email for help but had nothing back and have subscription active.
There is a bug with the Email Subject field in the Menu item parameters.
Try adding a space, or any other text if desired, to the Email Subject (optional) field in the menu item parameters. There are two instances, one for the Sidebar Search Results, and one in the Map Bubble Settings.