Hi Andrew -
I've seen this error before and had the same experience. It seems to be a corruption of the Analysis Services repository and copying or recreating the object is the only fix I've found.
One note: you can migrate the repository to SQL Server (it's an Access database by default). This may not prevent you from having the problem in the future but my experience is that this is a more dependable environment.
To migrate the repository: right click on the server object in Analysis Manager. Choose 'Migrate Repository...'
Scot J Reagin
sreagin@aspirity.com
Scot J Reagin
sreagin@hitachiconsulting.com