When I click wyUpdate.exe it says "Could not find file 'F:\Syncdocs64Portable\iuclient.iuc'". And I can confirm that no such file exists in that directory. I downloaded the 64-bit portable version from the website and that's what it does. Didn't try other versions.
Also, I tried searching for this: you can see the results at http://www.syncdocs.com/forums/search.php?q=wyupdate.exe
If you scroll down to the "Relevant posts" section, you'll see a bunch of links - but the URLs for all these links are http://www.syncdocs.com/forums/topic/#post- so there's a bug there. #5 Check for updates fails Posted November 16, 2014 - 03:41 PM looks relevant but when I tried the Google search for it, I got nothing.
Also, when I make this post it defaults to posting it into Announcements which doesn't seem quite right...