SYMPTOMS:
In Oracle Payables, when user click on all distributions for one invoice, using the invoice workbench form (APXINWKB.fmb), the following error occurs:

Steps to reproduce the issue:
Payables Manager responsibility
1. Navigate to Invoices : Inquiry > Invoices
2. Query the invoice
3. Click on all distributions
4. The error is displayed
Cause:
Workflow builder was not properly set.
SOLUTION:
In test instance where the issue exists, please do the following:
1. Go in Workflow builder > choose End process FND_FLEX_END_GENERATION > Click right > Choose Properties> in “Activity” tab for “Result Type” choose Flexfield Result > OK.
2. Open FND_FLEX_END_GENERATION > Go to the “Node” tab. For “Result” select “Success”.
3. Retest your issue.
4. If the issue is resolved, please migrate the solution as appropriate to other environments.