You did install the QlikView Microsoft IIS Support component/Settings service on the server running IIS, correct? That is the only thing of which I can think given the error seems to indicate .Net cannot find the QVIISWebServer instance, and the only way I believe that would occur is you did not install the Microsoft IIS component and Client Files on the IIS server. If you can provide some further details on how things are configured and how you are getting from SFDC to QlikView, that may help us provide a better answer here. Sorry I do not have anything better at the moment.
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