Or if you are using Perspectives you could have also forgotten to make the hierarchy visible in this perspective.

Have you migrated your repository to a SQL Server database or is it still in the MS Access database? If the latter is the case I want to recommend that...

have you set the relationship in the right direction? this error may occure when you've set the relationship by dragging from the id column of the dim table to the...

Open the properties of the attribute in BIDS. Click the ... button of the KeyColumns property. Now change the datatype to BigInt

Unfortunately that is not possible since the data is in a field which is of the NTEXT Data Type.