This happened to me on a Windows Server 2008 x64 machine, after booting it up from a hard failure. The version was 4.1. I tried upgrading to version 4.1.2 but that didn’t help.
What you need to do is delete the user.config file in the directory that the error message specified. For me it was this – C:\Users\Administrator\AppData\local\Veeam_Software\Veeam.Backup.Shell.exe_Url_5n5msbmzpxzk2bosrjjphdqtavmpm2jv\188.8.131.52 it may be different for other users.
Restart Veeam 4.1.x and you should be back in business.