I had the same situation on that.
I think you have to below Internet option dialog settings (IE).
- log on to host server by the account who is running QlikView server
- open IE -> Internet option -> security tab -> Sites
- add your sharepoint server url (http://SHAREPOINTSERVER)
Now the system account will be able to access to the sharepoint. Good luck!
Did you ever get a solution to this? I have the same issue ... out of interest where you using Qlikview web server for QV or IIS? I am using Qlikview web server on one server for QV and trying to access sharepoint on another server but that is using IIS .... I am wondering if I should reconfigure Qlikview on IIS.