Ok, I'm having to make informed guesses now as I'm at the limit of what I have picked up over the years, but ...
When you install an application it may load a number of files specifically for its own use into a directory. But it may also load commonly used files in to a common directory for both it and other applications to use. (It saves space not to have multiple identical files on your disk with different applications each using its own version.)
When your application needs to use this common file it will send it a message saying, "do this thing for me and let me know how it went". If the common file knows how to do whatever has been requested, it does it and sends the result back to the application. All is ok.
But if for some reason the common file doesn't know how to do what has been requested of it, it sends back a message saying, "I don't even know where to start on that, go away".
When you get the "no entry point" type message it is basically saying that a file was asked to do something, but it didn't know how to start doing it.
This could be due to corruption of the common file. Or a rogue application you've installed recently may have overwritten a later version of the common file with an older version, one that can't do as many things as the new version can.
I'm just wondering if you would have more success re-installing the Google desktop rather than trying to get rid of it. If it has been corrupted somehow I guess that might be a reason it's failing to uninstall.