Uncaught TypeError: Cannot read property '_leaflet_id' of undefined(…)

[am2222]

Hi,
I have faced this problem with leaflet while using this plugin,Is there any way to fix it?
thanks.
here is error
leaflet.js:5 Uncaught TypeError: Cannot read property '_leaflet_id' of undefined(…)stamp @ leaflet.js:5_on @ leaflet.js:5on @ leaflet.js:5whenReady @ leaflet.js:6addLayer @ leaflet.js:6(anonymous function) @ sc.js:42i

sc.js:42 is this code

map.addLayer(heatmap);

thanks very much