Running data integration import with a user provider as destination, suddenly throw following error. 
Any ideas how to debug this, or any solutions to the problem?
DW 8.2.1.0
| 5/14/2013 10:21:01 AM | Starting batch | |
| 5/14/2013 10:21:03 AM | Starting job - Import users. | |
| 5/14/2013 10:21:03 AM | reading configuration | |
| 5/14/2013 10:21:04 AM | Importing data to table: AccessUser | |
| 5/14/2013 10:21:04 AM | Job Failed with the following message: failed to move data from temporary table [dbo.AccessUserTempTableForBulkImport] to main table [dbo.AccessUser]. Reason: Subquery returned more than 1 value. This is not permitted when the subquery follows =, !=, <, <= , >, >= or when the subquery is used as an expression. | |
| 5/14/2013 10:21:04 AM | Finished job - Import users. | |
| 5/14/2013 10:21:04 AM | Batch failed. |