I am currently working on upgrading a customers warehouse and cubes from SQL Server 2005 to SQL Server 2008R2. The product does much the work for you but it doesnt solve all issues. After successfully upgrading my SSAS project I ran into some issues when trying to deploy the project. The error message (translated from Swedish) was "Error 103 The following system error occured: 0 0" (Error 103 Följande systemfel uppstod: 0 0 ) didnt help my much in understanding what was wrong.
Did a quick google to see what I could find, but no luck. So I started to go through the project, and for some reason I looked at the roles at first. And there it was! One of the roles contained a user which no longer exists in the active directory. Removed the user and heureka! the deployment was successfull!