Cannot read property 'dom' of null

[yamini23]

I am trying to include your plugin in our project. When i open Maths Symbol and type some equation and click okay, it is giving following error.

plugin.js:218 Uncaught TypeError: Cannot read property 'dom' of null
at plugin.js:218
at Class.onsubmit (plugin.js:270)
at Dispatcher.fire (tinymce.js:17048)
at Class.fire (theme.js:2778)
at Class.fire (theme.js:2784)
at Class.submit (theme.js:7029)
at Class.onclick (theme.js:5561)
at Dispatcher.fire (tinymce.js:17048)
at Class.fire (theme.js:2778)
at HTMLDivElement.delegate (theme.js:3168)
at executeHandlers (tinymce.js:1059)
at HTMLDivElement.defaultNativeHandler (tinymce.js:1075)