Shopping cart does not recuperate worklow

Hello, my SRM uses the BADI n steps.

A SC has been created. No workflow has been recuperated but a worklow is defined for the Z tables.

The status of the SC is Awaiting approval and when i click on the 'Approval overview' of the line item, it shows an error message : 'No workflow started.Application error occured!' .

No PO has been generated.

Is this a standard problem?

Anyone encountered this before?