DebugBar: Script Error in opening MapBox in IE

I can’t get out of the script error I am receiving in Internet Explorer when trying to open MapBox.
The error appears in the maps of my tile stream.
This works well before, but I can’t continue now. Does anyone have an idea about this?
Can you help me?

DebugBar: Script Error
A script error occurred in this page. You can send a page screenshot with script error description and useful other information by clicking the “Email” button. You can view this dialog again by clicking the script error Notification button on the Debug Toolbar.
Line:1
Character: 178373
Code: 0
Error Message: Unable to get value of the property
‘className’: object is null or undefined
