I encountered this error on a test server just now, and found something interesting in the error logs.  Some of the failed imports, out of the 48 that failed, popped out an error in the logs:

CRRGW5628E An com.microsoft.sqlserver.jdbc.SQLServerException error occurred when validating the input SQL string, caused by A processing error "Cannot resolve the collation conflict between "SQL_Latin1_General_CP437_CS_AS" and "SQL_Latin1_General_CP1_CS_AS" in the concat operation." occurred.

Data warehouse databases are supposed to be SQL_Latin1_General_CP1_CS_AS, as in previous versions of CLM, and the DB setup instructions for even the latest version seem to agree with me.  To check though, we switched this data warehouse collation to CP437 and tried to import the reports again, and now 27 were imported though there were still errors.  Some of the errors were still that collation mismatch, and some were what OP posted.  Our rs in this environment is in the same WebSphere profile as the rest of CLM and was set up correctly, so that error doesn't make sense unless for some whacky reason we need to add an outgoing/ingoing trusted friends relationship in 5.0.2 JRS setup even though it's the same Jazz server.  That doesn't make a whole lotta sense though.

Still working through this one and I know this thread is old, but I didn't find anyone else talking about this error and I just want to make sure the info is available.