error 429 after registry modification

- Sorry for bad English -
When I am using the createobject statement from my .xla to create a reference to my ActiveX exe, error 429 will occur. This error only occurs when i run code that modifies the registry prior to the createobject statement. What could be the problem?

You don't have administrator priviledge.

could there be another problem? (i am using the administrator account)
thanks