Did you already try to uninstall it manually?
My current workflow for creating new packages (uninstall OR install) is:
- Manually run the installer/uninstaller on a testing-device and check what it does (regshot, folder-monitoring aso.)
- Run the executable from the command line with the silent parameter and check again what THIS does (should do the same changes as without parameter, but sometimes it's not)
- create the package and try it on the testing device
Your problem could either be that the silent-switch is not actually working, or maybe your deployment-credentials don't have the required permission.