Application Error RoboHTML\BaseStructureEditor.dll

Hello,

I am using RH Classic 2019 (14.0.7.004) with RoboHelp Server 10. We moved away from WebHelp Pro and began publishing successfully, however, sometimes intermittently, to Responsive Layout several months ago. Now the intermittent success seems ellusive- can't publish at all to Responsive Layout.

I get the dreaded Runtime Error and application crash when trying to publish to the RH Server. Seems to get hung on a.SWF captivate file but I can only see that briefly before the RH Classic 2019 application crashes.  Event Viewer points to the following

Log Name:      Application

Source:        Application Error

Date:          7/19/2019 10:08:20 AM

Event ID:      1000

Task Category: (100)

Level:         Error

Keywords:      Classic

User:          N/A

Description:

Faulting application name: RoboHTML.exe, version: 14.0.7.4, time stamp: 0x5cc97038

Faulting module name: BaseStructureEditor.dll, version: 14.0.7.4, time stamp: 0x5cc97135

Exception code: 0xc0000005

Fault offset: 0x0008a249

Faulting process id: 0x1968

Faulting application start time: 0x01d53e3852e547fe

Faulting application path: C:\Program Files\Adobe\Adobe RoboHelp 2019\RoboHTML\RoboHTML.exe

Faulting module path: C:\Program Files\Adobe\Adobe RoboHelp 2019\RoboHTML\BaseStructureEditor.dll

Report Id: 01a09c36-5371-45aa-a7fd-878442aab70d

Faulting package full name:

Faulting package-relative application ID:

Event Xml:

<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">

  <System>

    <Provider Name="Application Error" />

    <EventID Qualifiers="0">1000</EventID>

    <Level>2</Level>

    <Task>100</Task>

    <Keywords>0x80000000000000</Keywords>

    <TimeCreated SystemTime="2019-07-19T14:08:20.433141800Z" />

    <EventRecordID>9793</EventRecordID>

    <Channel>Application</Channel>

    <Computer>VA-JTC001-L2.Corporate.S600605-AD01.corp</Computer>

    <Security />

  </System>

  <EventData>

    <Data>RoboHTML.exe</Data>

    <Data>14.0.7.4</Data>

    <Data>5cc97038</Data>

    <Data>BaseStructureEditor.dll</Data>

    <Data>14.0.7.4</Data>

    <Data>5cc97135</Data>

    <Data>c0000005</Data>

    <Data>0008a249</Data>

    <Data>1968</Data>

    <Data>01d53e3852e547fe</Data>

    <Data>C:\Program Files\Adobe\Adobe RoboHelp 2019\RoboHTML\RoboHTML.exe</Data>

    <Data>C:\Program Files\Adobe\Adobe RoboHelp 2019\RoboHTML\BaseStructureEditor.dll</Data>

    <Data>01a09c36-5371-45aa-a7fd-878442aab70d</Data>

    <Data>

    </Data>

    <Data>

    </Data>

  </EventData>

</Event>

Does anyone have any idea what this means? Can the .dll file be corrupted?

Other projects publish successfully.