There was a case, that a program wasn't able to update, because it wanted to uninstall the older version, but this wasn't able the old version was uninstalled manually (not my fault).
But it's very easy to solve this problem:
- Press "Windows-Key"
- Go on "Accomplish"
- Type "regedit" and press "enter"
- Search for the Registry-Entry, who should be uninstalled
- delete the Registry-Entry
- Start the update again