BAQ export to change UD checkbox on QuoteHed error: BPM runtime caught an unexpected exception of 'MissingMethodException' type

, ,

version 10.2.400.14
I am trying to set up a BAQ export process to run a BPM on the post-processing GetList to update a checkbox on multiple quote records.
It works fine when I click the Get List button myself, but when I schedule it to run from the BAQ export process it gives me the error below.
Am I missing something or is this not possible in my version?

Exception occured:
Server Side Error
Server Side Exception
	Description: BPM runtime caught an unexpected exception of 'MissingMethodException' type.
See more info in the Inner Exception section of Exception Details.
	Program: AWL_AWL_QuoteReminders.GetList.dll
	Method: A002_CustomCodeAction
	Original Exception Type: MissingMethodException
	Server Trace Stack:    at Epicor.Customization.Bpm.Ubaq6E2DCD11D8C744C7A3CCF81C5367575C.GetListPostProcessingDirective_AWL_QuoteReminder_6703ACA14AA5425D980CDE335269200B.A002_CustomCodeAction()
   at Epicor.Customization.Bpm.Ubaq6E2DCD11D8C744C7A3CCF81C5367575C.GetListPostProcessingDirective_AWL_QuoteReminder_6703ACA14AA5425D980CDE335269200B.ExecuteCore()
   at Epicor.Customization.Bpm.DirectiveBase`3.Execute(TParam parameters) in C:\_Releases\ICE\ICE3.2.400.0\Source\Server\Internal\Lib\Epicor.Customization.Bpm\DirectiveBase.Generic.cs:line 146


foreach (var ttResultsRow in ttResults.Where(row=> row.Unchanged()))

var QuoteHed = Db.QuoteHed.Where(row=> row.Company == CompanyID && row.QuoteNum == ttResultsRow.QuoteHed_QuoteNum).FirstOrDefault();
if (QuoteHed != null)
    QuoteHed.QuoteReminder_c = ttResultsRow.QuoteHed_QuoteReminder_c;