Solution : https://service.sap.com/sap/support/notes/514814 (SAP Service marketplace login required)
Summary : 
      When creating an order in APO using PPM with both standard and parallel sequences including operations and activities, an error stating 'Activity net contains a cycle' may appear. This results from a software defect and requires pre-existing note 504895. Resolution involves applying source code modifications detailed in the note, retransferring PPMs from R/3 to APO using specified transactions and reports, and considering specific wait and move times between operations in the sequences.
Key words : 
source code corrections, minimum wait time, terms manufacturing order, error 'activity net, sapapo/prod 045 reason, cycle' parallel sequence, 'activity net, program error, 045/sapapo/prod, 045 /sapapo/prod
Related Notes : 
       
| 555769 | R/3->APO: Missing relationships with parallel sequences | 
| 504895 | R/3->APO: Parallel sequences: Order and PPM integration | 
| 497808 | Queue error due to incorrect master data (RC 144, 145, etc) | 
| 437400 | Alternative and parallel sequences in APO integration | 
| 414717 | Missing move times at PPM transfer from R/3 | 
| 357867 | CIF-PPM: Transfer of data changes | 
| 332021 | Queue entry: Activity network not complete |