DOM Exception 5 on Safari Browser

Everyone,

       I am working on web application with Telerik controls. I am facing browser issue on Safari browser & its working fine on other browsers Firefox, IE, Chrome etc.

I have provided below error snippets:

convertfonttospanfilter error in safari
Error While executing filter ConvertFontToSpanFilter
-Error INVALID_CHARACTER_ERR: DOM Exception 5

Can anybody help this one to sort out.