Sharepoint 2007 - Server Farm Configuration Not Complete

Along with many others my MOSS 2007 Farm has been running for some time saying that it's configuration is not complete.

This was starting to get annoying so I decided to investigate. I deleted all the Administrator Tasks and ensured all the services were running where they should be. I even went to the extent of ensuring everything that could be configured was configured. The only thing remaining was to switch on farm features that I did not want, so I switched on Excel Calculation Services and started the service on one WFE server. The message went away! I was then able to stop the service and switch off the feature and the message did not come back.