I really don't know whats going wrong with your app. It should be able to see and even write (on a virtually stored copy) at the database file. You could give a try to changing
Qt Code: 
  1. <requestedExecutionLevel level="asInvoker" uiAccess="false"/>
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to
Qt Code: 
  1. <requestedExecutionLevel level="requireAdministrator" />
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And test if it works fine. But this a weird thing to do. I can't be of more help on just trying to figure things out... But I have a Vista test environment and, if your project isn't a proprietary software (or if it is and you trust me (I know you don't have reasons to do so, but...)), you could send it to me, so i could try to figure out what's wrong. =]

Cheers,
tinsukE