Proper way to use BPM to update OrderRel

Epicor ERP 10
,
24

@josecgomez
I am running this code:

using (var so = Ice.Assemblies.ServiceRenderer.GetService<Erp.Contracts.SalesOrderSvcContract>(Db))
				{
					var dp = so.GetByID(orderNum);   //variable 'ds' is changed to 'dp' since 'ds' is already used as a parameter
					for (int i = 0; i < dp.OrderRel.Count; i++)
					{
						if (dp.OrderRel[i].OrderLine == quoteDtl.OrderLine)
						{
							dp.OrderRel[i].RowMod = "U";						
						}
					}
					so.ChangeMake(false, ref dp);
					so.ChangeOrderRelBuyToOrder(true, ref dp);
					so.Update(ref dp);
				}

This is the error we are getting.

Description: BPM runtime caught an unexpected exception of ‘EntityException’ type.
See more info in the Inner Exception section of Exception Details.
Inner Exception: The partner transaction manager has disabled its support for remote/network transactions. (Exception from HRESULT: 0x8004D025)
The partner transaction manager has disabled its support for remote/network transactions. (Exception from HRESULT: 0x8004D025)

Even if we comment out change make and changeorderrelbuytoorder we still get the error. Something else is missing.