Looks like the root of the problem is renaming the Parallels Desktop application bundle or moving it somewhere outside the Applications folder. The update installer expects it in Applications folder and fails in case nothing is found.
We are already working on the problem. There are two options available:
Option 1
1. Quit Parallels Desktop.
2. If you renamed Parallels Desktop application to something else, rename it back to Parallels Desktop.
3. If you moved Parallels Desktop application to some other folder (say, Desktop), move it back to Applications root.
4. Launch Parallels Desktop from Applications, run the update and wait till it's finished.
5. (optional) Move/rename the application like you're used to.
Option 2
Wait a day or two while we are fixing the problem, and re-check for updates. It will update successfully.
Last edited: Jan 27, 2009