You should have full access if you only use the one account.
Did you reboot the computer after updating the game? The patch shouldn't need to change anything that requires a reboot (maybe Impulse's copy protection?), but it may help or remove conflicts (ie if the patch crashed on exit and left stuff in memory).
If you run the 'Verify Installation' program again, does it report any problems?
As far as I know the 1.005 patch (original download version was 1.004, though I would have thought they would update the main download package) consisted of updated div.exe and configtool.exe files.
Try deleting the files config.div, slashed.cfg and slashed-d3d6.cfg in the '..\Divine Divinity\Run' folder (if they exist), and see if that forces the configuration program to recreate them when you next try to start the game.
Assuming you still have and/or backed up the game download, you could try an un-install, reboot, and re-install (after making sure there was nothing left in the install folder besides the saved games). I wouldn't re-download the game unless nothing else helps, though.