CRM - How to Purge Obsolete Workflow Runtime Data - R12

Hello,

Connected as sysadmin user.A lot of error messages "Error in workflow JTFBRMPR ..." are displayed. To delete them, i have launched the request "Purge Obsolete Workflow Runtime Data" :           Item Type System: Errors            Age 0          Persistence Type Temporary           Core Workflow Only Y           Commit Frequency 500using OAM -> System Administrator -> Workflow -> Purge (UP). But the request has successfully completed and the same error messages still exists.Same result when executing the following code for some item_key specified in the system error messages:BEGINWF_ENGINE.abortProcess('WFERROR', i.item_key); COMMIT;
END;What can i do (The doc id 804622.1 is very long...)?Thanks in advance,Armel.