If you can't remove the application, then it means it's probably running or it's accessed by another one, like when you have two camera applications and one is using the stream and the other application can't access it. Try closing all the applications and then perform another uninstall. If you still encounter errors, try using Revo Uninstaller. Even if it can't uninstall the application normally, it will force it to uninstall by wiping out all traces of its presence from the system.
Additionally, if you encounter problems with the downloads, it's possible that there is no download link available or the website you're trying to download is experiencing problems.