Skumar,
There is no such thing as an Activity Rule for an MPS Message. I assume you are using P3411 to Process a Message generated from the R3482? I also assume you are Processing a Message for a Purchased Item (check the Stocking Type)?
In the Processing Options to your version of P3411 you will find the Next Status, Doc Type & Line Type the Puchase Order will adopt, when it is created by Processing an Order Message (Type "O"). Therefore, P3411 cannot let you create a Purchase Order for an item if the Purchasing Status Flow Rules do not support that combination of Status/Doc/Line Type. The same problem will occur for Transfer Orders if using DRP. (Mfg Work Orders do not have Status Flow Processing.)
By the way, the use of the acronyms "MPS", "MRP" & "DRP" is almost a question of semantics when discussing P3411.
