You have confirmed all of the requirements for QBI are as outlined in the QBI Help documentation - for example for QBI 6 at step #1 of http://www.ayanova.com/QBI6webHelp/installationdatabaseconfiguration.htm
and although you have QuickBOoks running on your computer with your QuickBooks database open as per the steps, when you run QBI, you get the message : " "
Quickbooks doesn’t appear to be open on this computer.
Start QuickBooks and open your company file now to proceed"
This is because one of those requirements actually have not been met.
Usually this is because you have not applied the QuickBooks updates - which is identified as a requirement before running QBI.
In QuickBooks, select to update, download all updates, exit out of QuickBooks, and run QuickBooks again - this is when it applies the updates. Once all updates have been applied, than run QBI
If you encounter an issue, always double-check the steps as 99.9% of issues are because one or more steps has been missed.