Quickbooks Web Connector Error - length cannot be less than zero

Question

Trying to connect Quickbooks Web Connector from one computer to another

<?xml version="1.0"?>
<QBWCXML>
    <AppName>QuickBooks WC Test</AppName>
    <AppID />
    <AppURL>https://localhost3.dd</AppURL>
    <AppDescription>Test</AppDescription>
    <AppSupport>https://localhost3.dd</AppSupport>
    <UserName>Admin</UserName>
    <OwnerID>{90A44FB7-33D9-4815-AC85-AC86A7E7D1EB}</OwnerID>
    <FileID>{57F3B9B6-86F1-4FCC-B1FF-967DE1813D20}</FileID>
    <QBType>QBFS</QBType>
    <IsReadOnly>false</IsReadOnly>
</QBWCXML>

With my hosts set to this:

<IP of other comp>  localhost3
<IP of other comp>  localhost3.dd

And the URL on the other computer being https://localhost3.dd at port 8443

However I am getting the error:

Length cannot be less than zero.
Parameter name: length

The new application was not added.

Which seems to be a generic C# error.

And

Cannot access a disposed object.
Object name: 'QBWCOpenDialog'.

QBWC1051: The new application was not added

What would cause this? Is there some issue with the connection or with the XML I am using to connect?

EDIT with requested info:

Web Connector version is 2.1.0.30, Quickbooks version is Premier Professional Services Edition 2015. And this is the actual QWC file I'm using.

Here's the log file:

20120201.23:43:22 UTC   : QBWebConnector.CompanyFileLock.getLock() : Got Lock = LOCKED:DAN-PC:634637365991413480
20120201.23:43:22 UTC   : QBWebConnector.CompanyFileLock.Send_DataExtModRqXML() : XML dump follows: -

<?xml version="1.0"?><?qbxml version="11.0"?><QBXML><QBXMLMsgsRq onError="stopOnError"><DataExtModRq requestID="1"><DataExtMod><OwnerID>{57F3B9B1-86F1-4fcc-B1EE-566DE1813D20}</OwnerID><DataExtName>AppLock</DataExtName><OtherDataExtType>Company</OtherDataExtType><DataExtValue>UNLOCKED:DAN-PC</DataExtValue></DataExtMod></DataExtModRq></QBXMLMsgsRq></QBXML>

20120201.23:43:22 UTC   : QBWebConnector.CompanyFileLock.Send_DataExtModRqXML() : XML dump follows: -

<?xml version="1.0" ?>
<QBXML>
<QBXMLMsgsRs>
<DataExtModRs requestID="1" statusCode="0" statusSeverity="Info" statusMessage="Status OK">
<DataExtRet>
<OwnerID>{57F3B9B1-86F1-4FCC-B1EE-566DE1813D20}</OwnerID>
<DataExtName>AppLock</DataExtName>
<DataExtType>STR255TYPE</DataExtType>
<DataExtValue>UNLOCKED:DAN-PC</DataExtValue>
</DataExtRet>
</DataExtModRs>
</QBXMLMsgsRs>
</QBXML>


20120201.23:43:22 UTC   : QBWebConnector.CompanyFileLock.unsetLock() : Company file has been unlocked for ownerID = <{57F3B9B1-86F1-4fcc-B1EE-566DE1813D20}>
20120201.23:43:22 UTC   : QBWebConnector.SOAPWebService.update() : Company file has been unlocked.
20120201.23:43:22 UTC   : QBWebConnector.SOAPWebService.update() : Ending session to QuickBooks.
20120201.23:43:22 UTC   : QBWebConnector.SOAPWebService.DisconnectFromQB() : Session ended and connection closed
20120201.23:43:22 UTC   : QBWebConnector.SOAPWebService.do_closeConnection() : *** Calling closeConnection() with following parameter:<wcTicket="2J3uBVZzBTEKl9x4izkjntfXvK1Fs6j8fdjX-wOluV0">
20120201.23:43:23 UTC   : QBWebConnector.SOAPWebService.do_closeConnection() : Received from closeConnection() following parameter:<ccResponse="OK">
20120201.23:43:23 UTC   : QBWebConnector.SOAPWebService.do_closeConnection() : CloseConnection called to application.
20120201.23:43:23 UTC   : QBWebConnector.SOAPWebService.do_closeConnection() : Response received from application = OK
20120201.23:43:23 UTC   : QBWebConnector.RegistryManager.setUpdateLock() : HKEY_CURRENT_USER\Software\Intuit\QBWebConnector\UpdateLock has been set to False
20120201.23:43:23 UTC   : QBWebConnector.RegistryManager.setUpdateLock() : ********************* Update session unlocked *********************
20120201.23:43:23 UTC   : QBWebConnector.SOAPWebService.update() : update completed.
20120201.23:43:23 UTC   : QBWebConnector.WebServiceManager.DoUpdateSelected() : Update for application = 'Motawi Quickbooks' has COMPLETED
20120201.23:43:23 UTC   : QBWebConnector.WebServiceManager.DoUpdateSelected() : Update session has ended.
20120712.14:51:56 UTC   : QBWebConnector.RegistryManager.setUpdateLock() : HKEY_CURRENT_USER\Software\Intuit\QBWebConnector\UpdateLock has been set to False
20120712.14:51:56 UTC   : QBWebConnector.RegistryManager.setUpdateLock() : ********************* Update session unlocked *********************
20120712.14:51:56 UTC   : StopFlexConnector : Object reference not set to an instance of an object.
20120712.14:51:56 UTC   : StopFlexConnector :    at QBWebConnector.QBWebConnector.StopFlexConnector()

Answer 1

Got same error and it started working when adding a trailing slash to the end of the <AppUrl> url value