Floating Social conflicts with third-party store locator plug-in

Hi, I was able to isolate Floating Social as the reason why the map markers in my SimpleMap plug-in were not being displayed. (If FS plug-in is activated, the locator returns "No results found" in the display.)

Does anyone have an idea why this is happening? I haven't asked SimpleMap because they rarely respond.

Here's the link to the site with FS turned off.