[1] PRB: 'Object Has Failed to Load' Error Message from Editor (2015-06-23 02:32:20 +09:00 版) https://support.microsoft.com/ja-jp/kb/190941/en-us

When an ActiveX control without a User-Interface is inserted into a page in Source view, or when Source view is activated for a page that contains a control without a User-Interface, an error message box appears that states the following:
>An object has failed to load. The object will be displayed as text.
Source view is attempting to render the control graphically but cannot because the control has not defined a design-time graphical interface for itself.
When a control without a User-Interface is inserted into a page in Source view from the Toolbox, the error message cannot be avoided.
To avoid receiving the error message whenever you switch to Source view, add an attribute called "viewastext" to the <object> tag that defines the ActiveX control that does not have a User-Interface. This will prevent Source view from attempting to render the control graphically, for example:
<OBJECT VIEWASTEXT CLASSID="clsid:B0A6BAE2-AAF0-11D0-A152-00A0C908DB96"
ID=SequencerControl1>