The only way that should happen is if you check the Disable Modify, Disable Repair and Disable Remove boxes in the Install Parameters page.
Otherwise, please send me the two MSIs (to support at advanced installer dot com) so I can reproduce this problem.
To uninstall a product by hand call "msiexec.exe /x [ProductCode]" from the command line. You can find out the ProductCode from the AIP file.
Hope this helps,