Diagnosis
There are records in the target table with the same key as records thatare about to be imported from the source client.

Procedure
Since there is a duplicate key problem, compare the datasets for thegiven category in both the source and the target client and decide whichversion you want to have in the target system.
Then run the post-processing report for document flow client copy(/SCMB/FLOW_CC_POST_PROCESS) and choose the option you want to use toclean up the duplicate situation.