Hi Melvin,
Is this happening on Control parameters update?
I think this should happen when sequence number mismatch sequence no between /SAPTRX/EH_HDR and /SAPTRX/EH_STHST.
Check this discussion.
Runtime Error : DBSQL_DUPLICATE_KEY_ERROR | SCN
Can you tell us how your are updating control parameter like custom activity or method or using standard activity or method in ruleset.
Regards
GGOPII