Error in Delete Audit Data

Hello Team-

I am trying to delete the audit data using the standard process chain /CPMB/ARCHIVE_ACTIVITY but getting error.

can someone help on this.

in the advance tab of the package code

(TEXT,%TIMESTAMP%,"Archive audit older than timestamp(YYYYMMDDHHMMSS)",)

(/CPMB/ARCHIVE_ACTIVITY,AUDIT_TIMESTAMP,%TIMESTAMP%)

(/CPMB/EXECUTE_BW_CHAIN,CHAIN_ID,/CPMB/ARCHIVE_ACTIVITY)

Package log error

[Selection]

--------------------------------------------------------------

TIMESTAMP = 20150428071509

[Message]

--------------------------------------------------------------

Failed to analyze instruction /CPMB/ARCHIVE_ACTIVITY,AUDIT_TIMESTAMP,%TIMESTAMP%

model: MGMT_INPUT. Package status: RUNNING

Thanks,

Ranjan