The new blogger interface will be applied to all blog in next month . Some of you updated to new blogger interface and error message suddenly appear when installing a new template . The reason is very simple . The error is on widgets in blogger and widgets inside template .
For example ,you added a Popular post widget to blogger when using old template . But in new template ,there's no Popular post widget in template itself . So error occurred. What to do in this situation is to remove Popular post widget in Blogger and re-install later . This is very different to old Blogger interface . The old one will show a dialog for all widget that not exist in new template and asking for keep these widgets or delete . We can still keep the old widget with all the code added in widget content . So I recomment you to : - Do backup before installing any template . - Copy widget content . - Remove all widgets - Install new template - Add widget back to template .