Doesn't make sense to me, it's hard to belive your code force this method triggering.
Are you in web client or in the Iteraction center? Are you creating a sales order or a service order? In which CRM version/SP are you?
BTW if what Harish Kumar suggested is not avoiding the DUMP then probably you have something wrong in config, and I mean functional config, otherwise I still recommend you to raise a message.
Cheers!
Luis