When I downloaded Hoiio for Windows Mobile installer to my desktop, my ZIP program prompts me to extract the installer contents. 

 Most Windows Mobile application installers use the .CAB extension and can be opened as a compressed archive. However, you should not open the CAB file as a compressed archive or extract its contents. Just copy it to your device and run the cab file - the installation process should start automatically.

I downloaded Hoiio for Windows Mobile successfully but installation could not start.

Make sure you are downloading the correct version for your device. You should download the Pocket PC version if you are using a touch-screen phone and the Smartphone version if you are using a non-touchscreen phone. Your phone needs to be running Windows Mobile 5.0 and above; Windows Mobile 2003 phones are not supported.

Hoiio for Windows Mobile has been successfully installed but could not launch. 

Before installing Hoiio, make sure that Microsoft .NET Compact Framework 2.0 is installed on your device. If your device is running Windows Mobile 6.0 and above, this component should have been installed. If you are using a Windows Mobile 5.0 device, you can download the component here. If you attempt to install Hoiio without the required components, you will see the following prompt:

Click Yes to download the required component. 

When download is completed, double-click on the downloaded CAB file to start the installation of .NET Compact Framework. After the installation is completed, you may proceed to install Hoiio. 

If you choose No when prompted to download .NET Compact Framework, the installation of Hoiio will still continue but Hoiio will not work properly. You will see the following error message when you attempt to use Hoiio:

When I uninstall Hoiio, I receive a message saying that the application could not be uninstalled. 

 Make sure that Hoiio is not running during uninstallation. Quit Hoiio and try to uninstall again. It is also possible that several files that are in use cannot be removed during uninstallation. Try to reboot the device and uninstall again.