There was a failure during installation of the Microsoft Exchange Data Conferencing service. Unable to write to the registry. Error code: {error code}; Message: {message id}

Details
Product:	Exchange
Event ID:	4100
Source:	MSExchangeT120
Version:	6.0
Component:	Conferencing Service
Symbolic Name:	MSG_INSTALL_CANT_WRITE_REGISTRY
Message:	There was a failure during installation of the Microsoft Exchange Data Conferencing service. Unable to write to the registry. Error code: {error code}; Message: {message id}

User Action
Verify that you have adequate write permissions, and then reinstall the Data Conferencing service.