Another illegal string offset 'id' fault

Hi there my wordpress site page: http://www.localsworld.com/map/ is showing the error warning: illegal string offset ‘id’ – the line it refers to in coding is written as: $id = $atts[‘id’];

I’m aware that somebody previously posted an illegal string offset id issue in the forum but changing [‘id’] to [“id”] did not fix the error and rolling back to a prior version of plug in did not seem to fix the fault. The previous forum chat has now been closed.

Please – anyone know how I can change the coding to remove the error? Most of the site was set up by a paid contractor but he is busy with other things at present and hoping to fix this minor fault. Thanks!