I am not certain I follow what is happening.
If you have an error on the DEF OBJECT you probably should force an error exit on the ON_CREATE otherwise your object will be instantiated without a valid Outlook object.
As for why the object creation fails, we have seen instances where Outlook itself is busy doing something (asking a user a question such as "Delete email?". updating mail from host, sending mail, updating calendar, ...) it doesn't accept a new connection.